MBA Entrance Exam

If you score between 96 to 99.5 percentile you have decent chances. Please check detailed cutoff below.
https://www.shiksha.com/mba/course/post-graduate-program-management-indian-institute-management-iim-a/1653

To prepare for CAT exam you need to do some self-preparation and you can also do some classes for good marks in CAT. You require some hard work to score good in CAT.

Admissions will be made on the basis of percentile/score in CAT-2016/GMAT, performance in academic writing test (AWT) and personal interview, academic (10th,12thand Graduation), co-curricular and extra-curricular achievements, and work experience. Start preparing by giving more mock exams.

Yes you can get into IIM Ahmedabad if you score well between 95-99 percentile.
https://www.shiksha.com/mba/course/post-graduate-program-management-indian-institute-management-iim-a/1653

Admission Open for MBA(RM) 2017-19 batch, Two-year full time residential MBA(RM) Programme KIIT School of Rural Management, KIIT University,
For More Information see www.ksrm.ac.in/web

MAT is not acceptable at IIM Ahmedabad, only CAT is acceptable.
https://www.shiksha.com/Indian-Institute-Of-Management-Ahmedabad-Iim-A-courses-offered-details-institute-college-listingcoursetab-307

You can join coaching institutes like TIME, CPLC, IMS. You need to devote at least 6 hours daily for preparation and maximum mock tests needs to be given before CAT exam in November so you get good practice.

Hi,
https://www.shiksha.com/mba/ranking/top-mba-colleges-india-accepting-mat/2-2-0-0-306
You can get details regarding fees, eligibility, placements and reviews in the above-mentioned link.

Chances depend on your CAT or GMAT score and without it you're not allowed for admissions. Let me know your scores and then I can predict accordingly.

Yes you do stand a chance to get admissionin PUMBA.The process for centralized admission starts in the month of May.Please follow the following website for regular updates: www.dtemaharashtra.gov.in