Getting into med-school?

Hi, I will be a high school junior this upcoming school year. And I am trying to figure out what career I wanted to be involved in. After thinking about it, I thought I would give medicine a chance, since I loved my Biology cl, and I like to help people. I have been a 4.0 student (barely, a lot of A-'s), I try to take all the honor and/or ap cles I can, I made into National Honors Society ( I think pure luck =] ), and I volunteer in an inter-faith dialogs. Now my question is what can I do right now that will help my chances to getting in med school. Some of my friends went to California ( Berkley) for a Medicine camp, I got the invitation also, but my family could not afford it. (This brings up the issue if cost will get in my way. Will it?) Am I really behind because of not being able to go to the camp? And would volunteering at my hospital also help me? Any advices? I wanted to go to University of Iowa's Carver College of Medicine, which is a pretty good med school. Thanks!