Here is the way I see it (anyone please correct me if I am wrong)
Your GPA and your GMAT score are the 2 quantitative elements an Adcom is going to be looking at first.
You can be part of the 70% of applicants who meet their expectations and have them look at the rest of your application
or you can be dinged right away.
Don't forget that they often have 5 times as much candidates than available slots...
Personally, I would work my ass off for an additional month, retake the exam and get a GMAT score above the median at the school you want to go to. Don't work this backwards: choose your B School, see what are their score requirements and then achieve the GMAT score needed.
Now, your GMAT and GPA are only 2 check boxes in your scorecard. If you really cannot retake the exam (why?) and have fantastic professional experience, extra curricular activities and have great essays, an Adcom is not going to see your GMAT score as the only reason to ding your application.
Remember: 50% of applicants are below the median...
Good luck whatever you decide to do!