MBA Entrance Exam

For TANCET, you must get top rank to get admission or else you have to take MAT exam and the fees varies for both.

Check the list of institutes accepting MAT scores for admission. The result of MAT September 2017 will be declared by the last week of September.

You can pursue MBA after MAT September exam but may get admission in next batch as majority of good MBA programmes start in June or July.

You have not specified for which college you are seeking information.

To prepare CAT and MAT, you can take help from any tutor, you can take guidance from mentor or can fix any coaching class.
You can study from online tutoring websites also. There are many websites where you can study online from teachers, sitting at your home.

If you get good percentile in CAT, maybe you won't have a problem in getting admission. Just work hard and study well.
If you need help for your CAT preparations, you can take classes from online tutoring websites also.

Definitely you should go for MBA. I am also doing B.Tech in CSE and will do MBA further. Firstly, you have to give CAT, MAT or GMAT exams through which you can get admission in IIM. I will suggest you to do MBA only from IIM or any reputed private colleges like LPU, BITS, etc.