Your MCAT and your performance in premed courses will definitely enhance your candidacy, but I wonder where that 2.9 comes from. You must have gotten almost all Cs in every class other than your premed courses. Even though you’ve shown you can handle the science, if those Cs are in upper level courses your work ethic might be at question. Then again, they may see your commitment to research as indicative of the fact that you simply chose certain priorities. Either way I would imagine that the 2.9 doesn’t knock you out of contention but it will make it hard to get into a top 50 school. Apply to plenty of lower tier schools (in addition to any top 50s you may particularly want) and you’ll have a chance of going somewhere.