OG should be your BIBLE, but as any theological scholar will tell you: you need much more than that. You need keys and commentary which without guidance it's difficult to figure out on your own...not impossible, but difficult.

Usually folks use other books in conjunction with the OG - - and even online material. We use a great online program that has over 8000 questions and gives you 360-degree understanding of math - - it seems that is what you need (only our clients have access to this material). In addition, it helps with timing and creating quizzes, based on what you get correct and wrong. Our big guns, however, are our kick ass tutors who efficiently and effectively size up your issues, and create customized action plans to get you through like a rockstar. There is NOTHING better than great material and a kick ass tutor who knows the material (not a script). Period.

In general: look at your strengths and weaknesses: I don't really know from what you wrote where your issues lie outside of the MATH in general. You need MORE to go on.

And don't forget the GMAC paper tests.