You've been given an answer with 24 perfect answers.
I do marvel at the fact you have been playing (and studying) piano for even a few years, and by the age of a high school senior planning to audition for the Eastman school you do not know of at least the 24 preludes and fugues
http://www.youtube.com/watch?v=3RjebdVKIAM
the six Partitas and the Italian Concerto. It is super surprising, if not shocking.
If you have not played this contrapuntal music before, I advise choosing a fugue with three voices. It will be challenging enough.
There are also a handful of 'Klavier' (= harpsichord or piano) Concerti
http://www.youtube.com/watch?v=v2I0tQIA_AE
several two-piano concerti
http://www.youtube.com/watch?v=6vbbnJ69Mc8
and miscellaneous other works for the keyboard.
Another famous keyboard work is the Goldberg Variations.
So I wonder where you've been, in what surroundings as far as teachers and peer group, and I think you might have some serious catching up to do. You might want to consider concentrating on piano for several years, leaving a majority of that time available for piano while taking a few gen ed courses at a local J.C. while working only a little part time before you try to gain acceptance as a university level music major anywhere. You may need this two years to 'catch up' if my estimate of your having missed some critical phases of musical and technical development is correct.
Best of luck and best regards, p.b.