What kind of job can I do along with my B.Com to gain work experience?

Back office jobs won't be of much help much, but being a part of different internship programs and projects will really be very helpful. This will add value to your MBA.

There is no such job, as it would degrade your credit. It is better to join up with an NGO and work with them. For further list of NGOs, do refer Google. This would help you to gain credits as well as to build foundation for a better future.