So are you African American and Mexican then?
Do you have any service to the AA or Mexican communities? You'll see gyngyn mention that all the time for URMS looking to apply to UC schools.
Your stats are fine. URMs with 3.7/28's historically have had alot of success. I wouldn't retake the MCAT. If you are looking for what to improve upon until you apply, service to the less fortunate and specifically to the communities you represent is something to give strong consideration to.