Your acceptance is based entirely on your idea (even though ideas are worth "nothing," heh) and your past projects. So learn some lisp to score brownie points and outsource a resume-filler project of your design to some cheep foreigners. You'll be ready to go.

As for hacking in general. The only way to learn is to create real programs. Books are a very small part of learning. I wouldn't recommend any.

Oh and don't tell the YC guys that you are hardly a hacker. They wont like that.