Hi Shrynit,
First off, a 650/Q48 is a solid Score, so it could be enough to get you into your first-choice School. As such, a retest might not be necessary. You're ultimately asking Admissions questions though, so you would likely find it beneficial to speak with an Admissions Expert about your overall profile. There's a Forum full of those Experts here:
https://gmatclub.com/forum/ask-admissio ... tants-124/If you do choose to retest, you might also choose to purchase the Enhanced Score Report. While the ESR doesn’t provide a lot of information, there are usually a few data points that we can use to define what went wrong on Test Day (and what you should work on to score higher). If you purchase the ESR, then I'll be happy to analyze it for you.
GMAT assassins aren't born, they're made,
Rich