Hmmm. Your undergrad cum is a little low, but not ridiculously so, so as long as you apply broadly you should be okay. Graduate GPA is calculated separately from undergrad, and doesn't count for as much (if anything), especially when not in the sciences. It sounds really interesting and I'm not trying to minimize it, I'm just saying it won't really work for you or against you. Your undergrad science GPA is very good, you don't need any work there!
Your volunteer work sounds great; is any of it medically-oriented? That could help. Working as a phlebotomist is good because it gives you patient contact, but shadowing is still a really good idea. That's the only way you'll understand what medicine is like from a physician's perspective, and will also let you explore areas of medicine that interest you. So I would try to get in some shadowing.
As to the MCAT, I would recommend taking it earlier rather than later. The BS section of the MCAT used to be 50% bio, 50% orgo, but this has shifted recently to favor bio fairly significantly (I would say my MCAT was about 70/30). And honestly, I don't think you actually need to TAKE orgo II to learn the relatively small amount of orgo II you need to know for the MCAT. That's just my opinion, but I would imagine that if you get a book or something to review MCAT orgo, you'll be fine. The advantage to taking the MCAT early is that your primary application can be complete early. If you take the MCAT in August, your scores won't be in until Sept, and while this isn't horrendously late in the game, it is best for EVERYONE -- particularly someone with an meh cGPA -- to apply as early as possible.
Overall, I think you're fairly solid, assuming you do well on the MCAT. Again, your cumulative GPA is a touch low, so really try to do well. I would aim for at least a 32. Get an MSAR, pick your schools carefully, and apply to a bunch. They are expensive as hell, especially once secondaries start coming in, but 30 is a good safe number.
Good luck!