What are some good pieces for me as a novice pianist?

I am 13 and I have decided to go ahead and use some of my free time doing something other than watch tv over summer since I am a quick learner. I have been playing for 1 week now and have mastered nothing. I need a good piece that will keep me interested but still easy enough to learn on my own. I need to play something good enough so my parents will buy me a real piano instead of the crappy keyboard I have now. Plzzzzzzzzzz help.