Hi mlevit89,
I noticed that you posted this in another Forum, but I imagine that other users here might also be interested in your situation, so I've copied my response here:
First off, a 670 is a strong score (it's right above the 80th percentile overall), so you might not need to retest. I would like to know a bit more about that score and your plans though:
1) When you scored 670, what were your Quant and Verbal Scaled Scores? Those numbers will provide some data on what you likely need to work on.
2) When are you planning to apply to Business School?
3) Have you thought about which Schools you want to apply to?
If you do end up retesting, beyond working on additional practice problems, it's likely that you need to learn and practice some new tactics.
GMAT assassins aren't born, they're made,
Rich