I gave up on AirPlay-enabled speakers myself; there's so little available, and most docks with it are overpriced for the sound quality.
For her room, I'd consider skipping AirPlay altogether and just go with a regular speaker dock--Altec Lansing and JBL make decent ones (I have one from each; the Altec Lansing is very good, and that's our main kitchen unit). Both do also make AirPlay capable models (Altec's will be out this fall), but the pricing versus features versus sound quality was such that it just wasn't worth it to me when I went hunting for a new setup a few weeks ago.
It was pretty disappointing; the functionality has been available for a year and I was expecting more models to be available. But instead, as HazyCloud suggested, I went the Airport Express route. A bookshelf stereo unit--that I've had for ten years!--paired with it just fine with a $13 cable, and the sound is incredibly rich compared to any actual "dock" I've tried. For anywhere you're going to use it on a regular basis, if you appreciate sound quality at all, this kind of setup is what I'd definitely recommend over trying to get an AirPlay specific model.