To be honest that should make you at least in the mix at UAB. The Master's would help not becasue your GPA is terrible, but it'd make you stand out. If you get a 4.0 in the Master's I'd say you should be accepted next cycle. You shouldn't retake the DAT your score is fine.
Did you have a lack of shadowing, or more importantly, not volunteering or extra curriculars that made you stand out? If you can find something you're passionate about that you can devote a lot of time/attention to, it'd make you stand out from the pack and increase your chances of acceptance just as much as a Master's would.
My vote is to do the Master's and do well (even some research during it if you can), get involved with some quality volunteering, and apply next cycle.
I'm no expert on UAB's admissions but this is the best I can come up with.
@hellofuturedentists would probably be able to be more helpful than I would.