Hey, 660 isn't so bad, either! There's really no single magic bullet that's going to get you from a 660 to a 720, but it sounds like there are plenty of things that you could do to improve.
For starters, it sounds like you've spent a relatively large amount of time with the Kaplan/PR/
MGMAT books, and relatively little time (comparatively) with official questions and practice tests. For your next round of studies, make sure you run through the questions in the official GMAT quant and verbal supplements, and you probably also want to pick up the GMATPrep Question Pack, available from mba.com or through your GMATPrep software. If you need more practice on CR and RC, consider doing some work from retired LSAT tests--they'll really help develop your ability to battle your way through dense, miserable language. It also sounds like you might be overstretched a little bit, so it's possible that fatigue hurt your verbal score somewhat, and a combination of tons of practice and a more relaxed student lifestyle might help you out next time.
And you definitely need more practice tests! Do some
MGMAT CATs, at least for quant, and take the GMATPrep tests once you're closer to your test date--the GMATPrep is the closest you'll ever find to the real thing.
I know that the 660 isn't what you were looking for, but it's a darned respectable score, especially considering that you didn't feel completely prepared. Imagine what you can accomplish once you have time to really do some methodical, consistent practice work! As soon as you feel confident with your preparations, go battle the beast again... and considering that you're not all that far off from a 700 already, I'm confident that you'll get to where you want to be. Good luck!