Tough call... no-one can tell you EXACTLY what GPA will be needed to get into med school! There was a kid at my undergrad who had a 3.9+ in Biochem, outstanding MCAT scores, got interviewed at every school to which he applied... and didn't get in anywhere.
He was smart, sure... he was also arrogant and a social idiot. Who wants that kind of doctor?
I am a current med student, and I also work with the admissions and recruiting offices pretty regularly at my school. I would say that if you are at a 3.0-3.2 GPA, as Dr. Admin points out, you will likely need some help.
Help comes in the form of kick-butt MCAT scores, a winning (and genuine) personality, maturity, and some form of awesome experience. For some people (like me) that experience could come through the military. For another, one might travel overseas and do amazing things as a photojournalist. For still other people, they may work at a clinic in Africa for a year. Whatever it is, if you are passionate about it, and it relates to medicine in some way, it will help.
The main thing is, you are more than the sum of your parts... or you should be, if you do it right.
Good luck, and keep on going for it. Med school sucks sometimes, but the payoff is worth it. (At least, it better be!)
CN