True, a 3.1 is not horrible; unfortunately, it's very low in the med school admissions game, since the average for matriculants is around a 3.6-3.7 these days. With that said, thankfully it's not so low that you can't raise it up to a decent number with some time.
Since you have to take organic chem, physics, and might want to retake chem 1 and 2, I suppose you are hoping to start this spring? To do this with the least amount of time, I'd retake Chem 1 in the spring (if you received a C or lower, otherwise I would just study from a book and not bother retaking it) and take Physics 1. You could then get rid of Chem 2 or Physics 2 in the summer, your choice. Then, you could take Organic Chem 1 and biochem in the fall, organic chem 2 in the spring, and take care of physics 2 sometime in one of those two semesters.
Since your GPA is low, it'd be best if you could take a full load of courses (~15 credits per semester). Take upper-division bio courses that you've never taken in undergrad. Still, if this is not an option because you absolutely have to work and can't see yourself living on loans (i.e. have a family to support), part-time will have to do. Still, assuming you took 15 credits for 3 semesters, and your current bachelor's affords you 128 credits @ a 3.1, with 3 semesters at a 4.0 (this is pretty important! An upward trend, fro ma 3.1--> 4.0, looks very good):
(3.1 * 128) + (45 * 4.0) = 576.8/173 = 3.33
Now, sure, a 3.33 is still very low, BUT not that bad. You could apply to an SMP and apply during that year. So, you'd hope to finish all undergrad classes by Spring 2009, take the MCAT as soon as you finish Organic 2, and hopefully get into an SMP in Fall 2009. This will be difficult, since by the time you'll finish Organic 2 and the MCAT, most SMPs will be full, I believe. However, if you took the GRE earlier in the year (January 2009 or maybe in 2008) and explained a strong interest to get into an SMP, some programs will probably let you in. Some of them will accept the GRE or DAT in place of the MCAT.
That's what I'd do, but this is obviously not the only route. I'm not sure how many med schools there are in Tennessee, but I think there's at least a few (meharry, ETSU, any more?)