Nawed123:
In all honesty, it probably won't help but it likely won't hurt either. It'll just be another component of your application that you can put on your resume and submit as part of your academic credentials. Obviously it would help to do well grade-wise (and doing poorly could actually work against you), but it's also not going to be considered equally with your undergraduate GPA. FWIW, a 3.5 GPA is generally fine for the Top 20 MBA programs, especially if you majored in a competitive field.
It's probably better if you do not abandon it. Quitting might be perceived as a negative, although I suppose you do not need to disclose you pursued this degree if you end up not completing it.
Is it possible to complete the degree and improve your hobbies/extracurricular activities? How time intensive is this degree? Also, when are you planning to apply? Are you looking at this fall or in a year or so from now? I would really only drop out of this program if you have a clear plan of action for pursuing a robust set of hobbies/extracurricular activities.
FYI, at some point in the process you might also have to explain why you decided to pursue a master degree in economics. Was this part of a larger professional strategy?
There's no easy answer, but I do feel like there are several unanswered questions that would help us advise you on the best course of action.