How should I get in contact with this girl?

Have your friend find out some details about her. Where does she like to hang out? Where does she go to church? What gym does she go to? The gym is a perfect place to "bump into" someone and strike up a conversation. Possibly your friend could suggest that a group of you and your friends (including your crush of course) could get together over the summer to stay in touch. Do you have facebook? Befriend her on facebook and, I know this sounds a little like creeping, find out more information about her such as her hobbies, where she works, etc. This could give you more insight and you can brainstorm more ways of "running into her". Hope that helps!