I pretty much failed my junior year, what now?

Your first step needs to be to your high school counselor office. Their job is to help you get the credits you need to graduate from high school. They will have information about summer courses, online courses, etc. If I were you, since you say many of the summer school courses are full, I would ask what online courses the school would accept to graduate. Tell the counselor you would like to graduate by summer 2012 and ask what you need to do to make that happen. It's fairly complicated about the various credits, etc. and only your counselor would know your particular school's requirements. Be proactive and ask the right sources--not anonymous strangers on Yahoo. Good luck to you.