Okay, so you did have timing issues on quant. (I'd be willing to bet you probably had some timing issues on verbal as well - almost everyone has timing issues, even though many people aren't aware of them.)
You also had some serious stress going on - you placed so much pressure on yourself that you must have been feeling even more anxiety on test day than you otherwise would have.
Did you take your practice tests under 100% official conditions? I'm trying to get a rough gauge of how far your scores dropped on the real test, so I need to know what could have led to artificial score increases. I'm ignoring the repeat-test scores. On the others, did you do essay and IR, limit yourself to two 8-minute breaks, etc?
You asked about materials. I'm biased. I'm of course going to tell you that I think our materials are the best. :) So what I'll tell you instead is: you need materials that are designed to teach you how to get better at the GMAT - both in terms of the actual content being tested and in terms of how to think through GMAT-format questions. For MGMAT, that would correspond to our strategy guides, our OG Archer program, and our practice tests. (And our classes, of course.) But other companies have these kinds of materials, too, so go do some research and figure out what you think will work best for you - then get those materials.
The two big things we need to talk about are HOW to study and WHAT to study.
WHAT:
all of the material in our strategy guides (or the equivalent if you use someone else's material)
HOW:
Read this entire article, but pay particular attention to the "how to study" section:
http://www.manhattangmat.com/blog/index ... -the-gmat/Then come back here if you have any questions. (And let me know your answer to my questions about the test conditions for your practice tests. I want to figure out whether there's anything you're doing that causes inflated scores and that we can change so that your practice scores more closely reflect what might happen on the real test. We can't, of coures, recreate the anxiety of knowing the real test is the real test, but there may be other things too.)