Colleges in Ahmedabad

There are many colleges which provide M.Sc. in microbiology. Here are some of the good colleges in Ahmedabad:
GUJARAT VIDYAPITH.
INSTITUTE OF Science.
NIRMA UNIVERSITY.
RAI UNIVERSITY.
MG Science INSTITUTE.
GUJARAT ARTS AND Science COLLEGE.

There are various scholarships that are available post seeking admission into IIM (A). One needs to score a minimum of 98+ percentile in CAT to get an invite for a PI (personal interview). Class 10th & 11th scores are not relevant here. You need at least 50% marks at your graduation level exams.

Admissions into IIMs are based on competitive Common Admission Test (CAT) score. To get into a top IIMs, one needs to at least score 98+ percentile in the test and then clear the personal interview (PI) round at the institute. You also need to have scored a minimum of 50% at the graduation level.

You need to take the CAT exam and then wait for the interview calls.

To be very frank it is difficult for you, unless you score a very high percentile in CAT. Nevertheless, there are other good colleges like XLRI or FMS that offer brilliant courses and you may wish to look at them.

You can easily get loans to cover all your fees related expenses.

You can also take GMAT and then apply for IIM's.

IIM-A does not offer BBA course, you may pursue BBA from another college and then apply for MBA.