The first real question is why do you want an MBA, that will give you a lot of answers to your own question. If you are looking to use it to get promoted within your current job or are you planning on changing careers? Honestly your best option would be to study hard, really focus on your weaknesses on the exam. This site provides some great advice for bringing your scores up. Then reevaluate your options. Most people who haven't already completed their applications by now are focusing on apps for next fall. So dont feel rushed to get anything out soon. Most schools don't advertising having minimums for the GMAT, even top programs let in people with weak scores if the rest of their application is amazing. So even with a low GMAT if you have a strong profile otherwise it may help your chances at a better school than you think you do, especially if you are an international student and had a strong quant but weak verbal.
Sadly I googled Keller and it is part of Devry which is one of those places that will take just about anyone who meets the basic minimums and are basically selling their degrees to people. Depending on your reasons for an MBA it may fit your goals but chances are it will cost you a decent sum of money and wont meet your expectations. So before doing anything research Devry as a university and the programs reputation and decide if it will get you what you want. Business Week has a great school database that will give you ideas, if a school doesn't show up there I would be cautious about attending it.
Really look at what you hope to get out of an MBA and determine if its attainable by attending any of the schools you are looking at. Generally part time programs are much easier to get into than fulltime so that may be an option if you can bring your GMAT up. As long as your goals are realistic for what the schools will provide and your understand what an MBA from a school will get you career wise then by all means go for it. And remember the worst thing that can happen if you retake the test is you don't improve your score and are out some time and money but at least you tried to improve your chances. There are several stories on here of people raising their scores very large amounts after prepping for a long time. A month of studying may not cut it, give yourself 2 or 3 and you will still have plenty of time to do apps for the fall.