I imagine this thread is dead, but in the event that you are still in this situation, allow me to be the voice of reason. Look at what she has told you, and make no assumptions. She said she was not interrested, if she did not mean it then she is the one who screwed up, but you should find someone more healthy.
I am not saying this is the case, because I do not have all the facts, but it sounds like she enjoys your desire to have her...but enjoys denying you her affections. Unless you have some sort of fetish for that sort of thing, you are only hurting yourself. I fully recomment that first on your list of girls you are attracted to, is that they are attracted back. Why waste energy on some girl who does not regard you highly enough?
In short, I don't know shit about you or her, but going from what she said....the longer you notice her existence, the worse yours will be.