Hi cpat,
First off, your initial 660/Q43 is a solid Score, so it could be enough to get you into your first-choice School (it would also likely be far better for your applications than your 650/Q37 would be). As such, an additional 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 and plans. Those Experts should be able to answer your Admissions questions and help define the specific areas of your profile that could use some improvement.
There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/If you do choose to retest, then you would not necessarily need to spend a lot of additional study time before doing so. You have an incredibly strong overall Verbal ability, so we would just need to make some adjustments to how you 'see' (and respond to) the Quant section. You do NOT need to be a 'math genius' to pick up a bunch of points in that section, but you will have to focus on learning and practicing the proper Tactics and training to take advantage of all of the built-in patterns that appear every day on the Official GMAT.
If you have any additional questions, then you can feel free to contact me directly at any time.
GMAT assassins aren't born, they're made,
Rich