B.Com

Eligibilty criteria to appear in CAT is that applicants should hold a Bachelors Degree with minimum 50 per cent marks or equivalent CGPA awarded by a recognised university or educational institute as incorporated by an Act of the Parliament or State legislature in India or declared to be deemed as a University under Section 3 of the UGC Act, 1956, or possess an equivalent qualification recognized by the Ministry of HRD, Government of India. For the reserved category candidates, such as Scheduled Caste (SC), Scheduled Tribe (ST) and Persons with Disability (PWD), the minimum percentage to be secured in Bachelors Degree is 45 per cent.
Candidates appearing for the final year of Bachelors degree/equivalent qualification examination and those who have completed degree requirements and are awaiting results are also eligible to apply. However, they will be given provisional admission only till the time they submit a certificate from the Principal / Registrar of their University/institution (issued on or before the date as stipulated by the respective IIM) stating that they have completed all the requirements for obtaining the Bachelors degree/equivalent qualification on the date of the issue of the certificate.
As you are student of 2nd year B.Com, you not eligible to appear in CAT.

NIMCET 2017 Eligibility Criteria:
Candidates must be Indian National
Candidates must be holding graduation degree I.e. BCA/B.Sc (Hons.)/B.Sc/BIT as per 10+2+3 pattern from a recognised university.
Candidates must have studied Mathematics or Statistics or equivalent subject during graduation degree.
General category candidates need to score at least 60% marks or 6.5 CGPA in aggregate of all subjects.
Candidates belonging to SC/ST category need to obtain at least 55% marks or 6.0 CGPA score on a 10 point scale in the aggregate of all subjects.
Candidates who have Bachelor of Engineering (BE) or B.Tech degree or equivalent degree are also eligible for NIMCET 2017.
Other conditions of NIMCET Eligibility Criteria 2017:
Candidates appearing for the qualifying degree examination are also eligible to apply for NIMCET 2017, however, they must provide the proof of qualifying examination at the time of admission
The conversion of scores from CGPA to percentage or percentage to CGPA is not permitted.
CGPA scores other than 10 point scale will be converted to 10 point scale as per unitary method.

Dear Anup,
For UPSC, one must know, "What not to study". Start preparing for current affairs from now onwards as it will become past till the time you get ready to appear for the exam. Keep your knowledge updated about everything that is happening near you, nationally and internationally. One should be able to speak on any topic reflecting that one knows about it. Carefully revise general studies as it will be with you if you are in the regular practice of reading it. Keep thorough and in-depth knowledge of your stream of graduation. Read as many news papers and books as you can. Reading itself will develop a new and confident personality of yours.
I hope this would suffice. All the best and god bless you.

Yes, you can pursue M.Com.
Some colleges in Kolkata are:
1) University of Calcutta
2) Goenka College of Commerce and Business Administration
3) The Bhawanipur Educational Society College
4) Shri Shikshayatan College
5) Ananda Mohan College
6) Scottish Church College
7) Prafulla Chandra College
8) Asutosh College
9) Bhairab Ganguly College
10) Derozio Memorial College
I will suggest you that with M.Com do some certificate course which can help you in developing your skills such as
1) Tally
2) Certificate course on forensic investigation
3) NCFM ( NSE certification in financial markets)
4) SAP FICO
5) Certificate course on EXIM
6) Digital Marketing
Else, prepare for banking exams, insolvency professional exams. And if you are thinking about earning while learning and want to seek practical knowledge then go for internship in the field you are interested in. Moreover, it will help you in identifying your interest in a particular branch/ field.
All the best.