Recommendations for Amharic textbooks?

My mom and stepdad have adopted an Ethiopian baby (her name's Hayat and she's awesome) and are in the process of adopting an Ethiopian little sister for her. Since I'm the language nerd of the family and am already studying a Semitic language (Classical Arabic), I feel like I ought to learn some Amharic.

I've discovered the FSI Amharic page and I'm sure it'll prove useful, but I'd really prefer to learn the Ge'ez script.

Have any of you had any experiences with introductory-level Amharic textbooks (especially those that use the Ge'ez script and/or have good audio components)? Are there any particularly good options, or textbooks I should avoid?

Thanks in advance!