I would advise trying to take the GMAT again before applying. While the GMAT is definitely the the beginning and end of your app, your score may be too low for you to get into your target schools. Dedicate yourself to some serious prep for a couple of months and then try again. You could still get in your apps for Round 2 of this year if you start now, but definitely don't rush it just for the sake of meeting a deadline. You may want to consider really taking your time to boost your GMAT score and then applying next year.
But, one thing I want to add is that no school has a GMAT *requirement*. Yeah, it will be hard to get into Kellogg with a 600 score, but it's been done. Schools don't have hard GMAT requirements. Those numbers that you see are just averages. The closer you are to the average, the better, but don't think that everyone at Kellogg scored 700+ on the GMAT! Try to get within your target schools' middle-80% range, and you'll be fine. You won't be guaranteed to get in, but your GMAT score probably won't keep you out, either.
Veritas Prep | GMAT Prep | MBA Admissions Consulting | Co-author, Your MBA Game Plan
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