There is no need for you to take GRE classes. Just buy the latest kaplan book with the CD and just practice daily and you will be fine. I took GRE Test late-- about a month before the deadlines for mph programs --and I studied only for 2 weeks and I was fine. I will be attending UMich this fall. Just make sure that you practice verbal and math daily! How I studied: I wrote down the vocab five times twice before going to sleep and early mornings and practiced math as much as I could. I was doing full-time research, so whenever I had downtime I would sit down with my GRE book and study and then after I was done with work, I would study for 2-3 hrs. GRE Test isn't as bad as you think it is. You will do great! 🙂
Good Luck!