I don't think this is an issue of whether or not you'll be able to improve your score - you pretty clearly will given that you barely studied Quant, and were not prepared for some easy to learn rules and topics. The question really is, what will it add to your profile?
From everyone I've talked to and everything I've seen, you're not going to have trouble getting in to the top schools with that GMAT. Your quant is a little low, but Quant experience should actually make up for it, because they care that you can learn and apply the methodologies that they teach you. One thing that I'm surprised no one has asked you is what do you plan to focus on in B-School? If you're thinking of writing your essays about how you want to be a Quantitative Finance Guru, then you might want to retake. If you want to get into marketing, on the other hand (completely on the other side of the spectrum, I know), then they really won't care.
Here's the bottom line: If you're willing to put in 4-8 more weeks of hard studying, which is what you'd probably have to do to really improve your math (I found that my math went down after studying for awhile, and took a decent amount of time to get back up and beyond where I started), then you may as well. If not, and you want to move on to having a normal life/preparing for Apps/adding to your overall candidate profile in other ways, then do that. I think you'll be fine if you do, but certainly can't blame anyone for wanting to do better.
Also, pretty impressive to score a 730 with minimal studying. Well done.