Hi melisa1,
First off, a 650/Q47 is a strong score (it's right around the 80th percentile overall), so it could be enough to get you into your first-choice School. As such, a retest might not be necessary. Depending on the Schools that you plan to apply to, you would likely find it beneficial to speak with an Admissions Expert about your overall profile. There's a Forum full of them here:
ask-admission-consultants-124/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 score results show that you essentially performed the same way each time (+/- a few points). By extension, this means that 'your way' of approaching the Exam would likely continue to earn you a score in the mid-to-high-600s. To score at a much higher level, you're going to have adjust how you 'see' (and respond to) this Test - in BOTH the Quant and Verbal sections. The large number of questions that you had to guess on implies that you're using some inefficient Tactics against this Test - and taking far too long to answer questions (when other, faster approaches would get you to the correct answer). To hit the 750+ level, you'll likely need to invest in some new materials and learn/practice some new Tactics. I suspect that you would need another 2 months of consistent, guided study to get up to that level.
Since you're just coming out of your Test, I think that you should definitely take a few days 'off' to relax - approaching this next phase of the process with a clear head would be a good idea. Remember that the GMAT is a consistent, predictable Exam, so you CAN train to score at a higher level. You're just going to have to adjust your routine a bit to earn that higher score. When you're ready to get back to it, you should post back here and we can talk through your timeline.
GMAT assassins aren't born, they're made,
Rich