Brian,
I think that the most important statement in your situation is "I am a horrible test taker".
To me this means that while you probably have all the knowledge and experience to pass the PMP exam, you "freeze up" during the actual exam and that you have trouble getting through the 200 questions in 4 hours.
My recommendation: Practice. Practice. Practice.
Unfortunately, my own PMP Exam Simulator will only come out in about 2 months, which is when you will already be a certified PMP. So for now, I recommend that you go ahead and subscribe to another Exam Simulator online and continue to practice exam questions. (i.e.
www.pm-prepcast.com/readysetpass
)
In this way you a) practice the exam and b) you can gauge where you have holes and must study the materials again. I believe that doing exam over exam over exam will be the best approach for you rather than taking yet another class.
Practice what you will be tested on.