It's good to hear that things are going well. Yes, I too would think it's best to prime the walls first especially if you DON'T know what you have for paint. Also, it's required work to prime if you're putting light paint over top of dark paint, or visa-versa. It prevents the colors from 'bleeding' through.
Anyway, as for closet organizers, the Home Centers and K-mart and such have choices. I can't recommend anything in particular. Just look at the parts and the install-info to see how things are built and put it. That should help with the quality aspect of things. My best to ya and hope this helps.