I think that ultimately it doesn't matter too much what pieces you play, except that you need to be able to play them very well and very musically. I think that playing musically is much more important than hanging on for dear life through a Transcendental Study or something.
What you've got now sounds good. If you are in doubt, you can always phone the place you'd like to apply to and find out more info from them. I did a lot of asking around and found students already at the school to talk to and asked them what they thought of what I was going to play.
Some music schools have very specific requirements on their websites, and they can help give you an idea on what another school might excpect you to play too.
At my audition, I played the last movement from Beethoven's sonata op. 10 no. 1, and a waltz by Chopin, op. 64 no. 3, and the Footsteps in the Snow prelude by Debussy (though they didn't ask me to play that one). As you can see, the things I picked to play weren't super hard, but I studied them with a microscope and was able to play them really well and I don't know but it might have left a better impression than say, a student who played much harder pieces but with less command.
Also, the interview is super important. You need to be able to say exactly why you want to study piano, and what your goals are.
For some reason, I found the audition not as scary as I thought, so don't panic too much.
I mean, my school wasn't the hardest to get into, but only six piano students were accepted, and I think that the thing that sold me to them was my wild enthusiasm in the interview and my attention to detail.
So there you go. That's my two cents on the subject. I hope I've helped you a bit. If you have any more questions, just ask.