Hi fast7,
I'm sorry to hear that Test Day didn't go as well as hoped. GMAC has publicly stated that the Official Score that you earn on Test Day is within +/- 30 points of actual ability. Assuming a similar 'swing' in how your CATs function, your Official Score shows that you essentially performed right in the 'middle' of your score range.
Earlier this month, you stated that your goal score was 700+, but now you've stated that it's 640+. The exact goal score that you're after is important, as it will help to define what you should do next. If your goal is 640+, then you could conceivably retest in 16 days and hit that mark without too much difficulty (you're essentially at that score 'level' right now; you just need to tweak how you go about dealing with the Exam). However, if you really want a 700+, then you're likely going to need another 1-2 months of consistent, guided study to hone your skills and consistently score at that level.
Since you don't appear to have any looming application deadlines, are there any external deadlines that you're facing (that involve other aspects of your life)?
GMAT assassins aren't born, they're made,
Rich