The quantitative score is way more important. If you're aiming for top 30 you should retake the exam IMO. If you've gotten high grades on the practice tests, then I'd chalk this one up to nerves and go again. My advice might be different if you really didn't think you could do better; there are rare cases of people getting admits from top schools with a 750Q...though most of them benefit from pedigree.
So all else equal, a great verbal score is better than a terrible one, but the verbal score is definitely not a substitute for a math score. I'm not sure exactly what you're asking in the last sentence, but your school's reputation alone will not preclude you from top programs. I'm from a top 100 undergrad econ program, now a top 15 PhD. Jeeves did even better, and there are other examples. Coupled with a bad GRE-Q score it'll be tough to get noticed, but if you get the GRE score fixed (and have some gems elsewhere in your profile) you can be competitive.