There are plenty of good schools that accept GMAT with 500 as lower limit, or even without a lower limit. I ran into them while searching for a 1-year MBA in the US. A good school in my terms means something which is accredited and gives you a decent education, but does probably not open doors to Wall Street or to top consulting companies. I hope that's not what you're after, because if you are, you will have to get a score in the upper 600s.
You could use the MBA search by Peterson's http://www.petersons.com/mba/code/search.asp
use your GMAT score as a search definition. In order to choose what is a good school for you, you must look for accreditation information, academics quality, and of course whether this program is suitable for your personal needs. Good luck.
One more thing: you mentioned you have some personal issues. Are you sure you can handle a tough MBA program, if you cannot see yourself studying for a second GMAT exam? I am saying this kindly and supportively. It seems like the MBA will be a tremendous strain for 1-2 years, requiring a balanced mind that can tolerate stress.