IIM Ahmedabad - Indian Institute of Management

It takes practice and only practice to crack CAT and I believe 20-15 mock tests are more than enough. Given that you will be practicing for standalone questions and problem sets as well. However if you think you need more mock tests, please go ahead and take those. Questions are not that difficult, you need to master speed and accuracy.

IIMs usually have cutoff for 10th and 12th marks and I am sorry to say you would not clear any cutoff with 37% in class 10th. However, IIMs also have a policy of inviting top ranker in CAT from different streams. Hence If you can score 99.98 and more, you will have a good chance of getting a call from IIMs. (if you get 100 percentile, you can be sure of calls from IIMs).

To apply for IIM Ahmedabad, you need to clear a minimum cutoff for 10th and 12th marks, which depends on your class 12th stream. Please look at the IIM. Ahmedabad website to find out the exact cutoff.
2 years gap should not be a problem, If you can reason it in the interview.

In my opinion, most people who wants to do an MBA know their reasons for it. Hence, if you are convinced that you should do an MBA, you should. Having said that, here is what probably you wanted to know. What if you go for an MBA at this stage of your, will it add any value?
The short answer is YES. However you should look for executive MBA as you might not get good placement post regular MBA. All IIMs offer executive MBA and general placement is also really good. Alternatively you can apply to ISB or other institute that require GMAT score.

It is widely recognised and enjoys good patronage. It has good infrastructure and situated at a reasonable distance from railway stations of Bengaluru. It is worth joining, for all I know.

I think it's bcom as in bcom you get an overall idea and your horizon is wider not just for MBA but for other professions as well.