IIMC Entrance Exam

Hi Harleen!
I would say that a comprehensive plan in studies will help you reach your target. The time table for the study plan should be in tune with your daily needs and schedule. As far as the preparation is concerned, I would suggest you to spend quality time everyday at reading journals, magazines, newspapers, etc. And for GK, you can refer Competition Success Review for updates on current affairs. You may also refer the following books:
Arihant Mass Communication Journalism Entrance Examination
Mass Communication and Journalism Entrance Examination by Dheeraj Pandey
Guide to Journalism and Mass Communication Entrance Examination by Students Aid Publication
Manorama Yearbook.

Hi!
It is time you put your worries aside, because journalism colleges welcome all - irrespective of which subject you studied during your graduation. To begin with you need to keep a close check on the form dates of all the good colleges which offer post graduation in journalism. For starters, Indian Institute of Mass Communication, Symbiosis (Pune), Jamia Millia Islamia, Times School of Journalism (Delhi), Asian College of Journalism (Chennai) and St. Xavier's College (Mumbai) are some of the best ones in India. There are others like Makhan Lal Chaturvedi University (Bhopal/Noida), Aligarh Muslim University and Banaras Hindu University - but despite having big names in the country, these universities aren't a good match for those students who are on a look out of placements.
The ones I mentioned as good offer placements with decent salary packages. Moreover, all you need to have handy is English/Hindi (whichever language you prefer) stronghold and current affairs on your tips. Some college entrances ask very basic Maths questions and history of media - which can be studied from any competitive book (I guess it was Arihant Publications is the best one).
Good Luck!