Dear Shewale
If you have already taken jee exam, you can get into any IITs NIT's and also some of the best private universities are BITSAT, VIT, SRM etc..,
All the best.

If you have tried for exams like
Viteee, srm jeee, bitsat etc and secured well
Then go with them
Otherwise Amity noida is best for you

One option is that you can try for improvement exam to improve your 12th percentage and also prepare for JEE and BITSAT. Because many exams and colleges have 75% as their cutoff. The other option , not suggested though you could try in some private tier 2 or 3 colleges.

Not many colleges accepts boards marks only for admissions...you have to give entrance exams for most of the colleges..but colleges like Chandigarh university and amity university can give admissions .....for amity university amityjee would be conducted.....so if you have given any entrance exam then try through them....all the best