What are my chances with Colleges?

I have a 32 on the ACT, but only a 3.45 GPA unweighted. I just finished my junior year and have already taken 7 AP classes. I am taking 6 more my senior year. I intern at a law firm and hold office of a couple of clubs in my school. I need to know if my average GPA will stop me from getting into a highly selective school. I am really aiming for Brown or UChicago, and I plan on taking the ACT again and hopefully scoring a 34, which I think is very very probable. Can anyone tell me what my chances are??