German resources?

Sounds like a pretty typical experience of a heritage language speaker. Unfortunately, I myself haven't found the learning method that suits me as a heritage language speaker. Hopefully other people can help. :)

Perhaps you might want to look at http://www.dw.de/ - there is a big "Learn German" section with all kinds of media, including "slowly spoken news", interactive courses, a specially produced soap opera...

OK, several points.

(a) Most textbooks are based on several "presuppositions", never clearly formulated. With all "new methods" around the truth is probably 99% of textbooks (a) teach grammar (b) introduce very "thin" slice of vocabulary and (c) demand that almost all material presented in a lesson was learned actively

Let mel explain what I mean.
(a) is more or less clear - all syllabi are measured by the grammar taught, center on it, and have as their major, major aim transferring the knowledge of grammar.

(b) "thin" treatment of vocabulary means that mentioning, say, "hand" (by pointing at a picture), textbook writers consider their task completed: "one more frequent word learned".
In reality a human being has a hand - you do things WITH your hands - something is IN your hands -- you HAND sth OVER, OUT, IN....
By hand; force someone's hand; (near) at hand; at the hands of; sth gives you a free hand; 2 things go hand in hand...
You clusp, clench, wring, fold, wash, extend, lay slap ...... your hands. Your hands may shake, reach out, catch, grip, hold, clamp

Most frequent words in any European language (at least) may have hundreds of meanings, and come in hundreds of collocations and set phrases that ANY NATIVE SPEAKER KNOWS perfectly and can immediately recall

NO FOREIGH LANGUAGE COURSE SYSTEMATICALLY TEACHES this vital information. They teach grammar.
As a result those courses "based on 2000 - 3000 most frequent words" do not deliver the knowledge which must be delivered to begin to understand the 80% of general texts (as statistical calculations show), because that coverage is possible only if all or most of the usages of the most common words are known to the learner.

(c) And finally, there is no intellectual activity among humans, I believe, where passive skills would not exceed active skills. None. So the textbook writers when in a new lesson they push more grammar on you, more vocabulary (in a wrong way, but still new), and then demand through the system called "exercises" that you retain and recall correctly nearly 100% of this information are involved in a process of torture, not learning. The difficulty turns a learner's motivation off.

NOW, WHAT CAN BE DONE?
I will describe below, in a second comment (as this one is becoming too long for LJ) a procedure I "invented" myself - but then discovered that others had done the same, and used it successfully.
I read about a 19-century European polyglot who followed a routine very similar to mine when learning languages, and today there is a young opera singer, who described his experiences in a book and keeps a web site about his approach.

But basically, you have to learn ALL meanings of the 2000-3000 most frequent words by reading their entries in a learner's dictionary for your language like a book - a book that explains itself, so you never need to break off to consult another book for explanations - according to some logic.
This reading will provide you with passive vocabulary (in my case, as a beginner in French, I reached a level sufficient to read Harry Potter books in French in just one month of 1.5 to 2-hour per day of such dictionary-reading sessions), which then will make it possible for you to get grammar and "activate" you passive knowledge much faster and easier.

Your dictionary could be one of the Langenscheidt's "Deutch als Fremdsprache" dictionaries (they have at least 3 for different levels).
Duden "Wo:rterbuch Deutsch als Fremdsprache" (republished by Hueber) is less useful. If you basic German is good enough, you might try an even better one "Wo:rterbuch Deutsch als Fremdsprache" by Gu:nter Kempke.

There is an on-line dictionary where words and example phrases are read by a text-to-speech program, but it is inferior as a book for learning. You can find this one at www.pons.eu (a bunch of bilingual dictionaries plus a monolingual for foreign learners of German)

(to be continued)

As a general textbook I'd like to recommend _Jannach's German for Reading Comprehension_, 7th edition, by Richard Alan Korb. (Disclaimer: I worked on this book.) I found it well-structured and taking much of the mystery out of weak and strong conjugations, etc etc. The only caveat I have is that you should learn cases as 'Nominativ, Genitiv, Dativ, Akkusativ' because other resources will refer to 'third case' and always, always ALWAYS mean the dative. Other than that, because the book is using real world texts rather than 'watch Spot run' I think it will work well for those times that you feel confused by books or audio sources and need to engage with the underlying grammar. (I speak too much German to know how useful the vocabulary-building part of the book is.)

The trouble is that Jannach's is, as the title says, meant for reading comprehension (I've used it because I need to have working knowledge of written German in order to read journal articles). The OP wants to learn conversational German, not improve her translating skills.

still completely baffled by cases, articles, and conjugation

Sounds to me as if a resource to unbaffle would not go amiss, and it also has ways (and strategies) to expand your vocabulary and a good number of conversational examples. I found the explanations very clear, and I like the choice of topics and examples.

One of the problems the OP will face is that a lot of Germans will wish to practice their English, so getting to an adult level of conversation - however basic and stumbling - will make the learning process much easier from there, and this is a book that has both vocabulary lists and at least some conversational examples. And I really liked the choice of topics (Art. Literature. Dinosaurs.) - it's not the typical 'where is the hotel' approach that 'practical' courses so often take.

I'm learning German right now and I am using:
http://www.memrise.com/courses/english/german/ for vocabulary
http://duolingo.com/ for reading comprehension, but it seems to be most useful for people who start from scratch like me.
http://www.dw.de/learn-german/german-courses/s-2547 (already mentioned) many resources here, but I am mostly using it for listening
http://www.italki.com/ for conversation and writing. I am just doing paid Skype lessons and using the notebook to give and get corrections at the moment since I'm still such a beginner, but you can also find language partners for Skype for free.