I would encourage you to re-try, first and foremost, since schools will take your highest score, and may even wonder why you DIDN'T try again with a score well below 600. No reason not to try, and if you put some time and effort into your preparation, I have seen many candidates improve 50-100 points when starting at the level you are at. It also just further shows your dedication to your MBA goals.
Otherwise it will be difficult to gain acceptance, even at the schools ranked 20-30 or thereabouts. If you re-take and happen to not improve much or at all, feel free to come back and discuss options... in general you will need very strong essays and to show what is unique about you and why you need the MBA to have a chance at any program, and strengthening that GMAT is pretty key as well.
Good luck to you on that GMAT !
Thanks for the reply. Yes even I am planning to attempt GMAT again but not immediately. I am taking a gap of 45 days again for my preparation and meanwhile I'm planning to sketch my essays also. By th time I give my GMAT (Say July end), I'll also be ready with my essays and even if I score less than before, it may not effect my time. Please tell me how is this plan and is it really worth a plan??