B-School "Total Package"

Few questions about B-school:

Little Background:
I am a NCAA D1 Athlete, I go to a top 30 undergrad business school, major in finance with a 3.60+ GPA. I am going to be a SA at a BB in IB this summer.

How important is GMAT Score?
I have never been that good of a standardized test taker, I have made it everywhere in sports and school and getting SA from non-target due to hard work.

What types of Extra activities should I be trying to get involved in to bolster my resume in terms of leadership/voulanteer experience?

Will the fact that I have taken 4-5 classes at community college prior to going to school make a difference? I took two years off to pursue my athletics, and took a few classes to keep my mind sharp. I will however complete my undergrad in 3 years taking extra classes while playing sports to make up for it.