Hey Nikhil! 

I would suggest you consider giving CAT again next year. As you already mentioned, you have a good score in the class eleventh and twelfth. So, if you are able to score near about 97-98 percentile in the upcoming year. You can very easily get IIM. If not the old one, at least the new ones. Plus, it will be a perfect ROI. As MBA courses are pretty expensive considering other Indian Educational Courses. Secondly, you will call from most of the Private colleges for MBA. So, work hard and ace CAT again. Or consider taking the most suitable college with your present CAT score. 

Based on your score you have decent chance to get a call from IBS Hyderabad, BIMTECH Greater Noida, Christ University Bangalore etc. You can also check your other chances with CAT Pathfinder Tool.

CAT Pathfinder Tool

Good Luck!