I will reiterate what MarkMass said.
I have a low GPA and this is my second cycle. I was prepared to reapply. I continued taking a class each semester to raise the GPA, began volunteering at a free clinic, beefed up the LOR's, started a website involving one of my passions. I wanted to show that I refuse to be stagnate and continue to develop.
So far I have two interviews this second cycle one of them being one of the best programs in the country. I am still taking a class each semester and continuing to volunteer, just in case I need to apply a 3rd cycle. Don't sleep and keep strengthening your app.
Definitely retake those courses, especially being pre-reqs with all C's.
Interviews are typically done at the site you have chosen and you will be notified about 1 month before.
interviews with MEDEX are fun! I had a few last year and I definitely enjoyed my time interviewing with the MEDEX faculty more than any other school. They really want to know YOU! That said, if you interview here, practice up on typical PA interview questions (there's a good book on Amazon). But add YOU into the answers.
I think I said this before, but invites will probably go out early to mid September.