I completely agree and encourage you to utilize your time effectively but at the same time do not lose focus from your B.Com(Hons.) programme. It is important that whatever you do you must score well. As far as your marketing course is concerned you can do a Bachelor's in marketing management from Pondicherry University through distance or can even think of learning a foreign language which would be an asset for you always. Focus on doing something through the regular mode and to be eligible for that you need to work hard and better your grades.

Hope that helps.
Counselor