you might want to check with each school that you are applying to for the latest possible/acceptable date of DAT. Some schools do have a certain deadline (i.e. UoP wants it no later than September; UCSF wants it by October 15). Given this cycle's fierce competition, you might be wasting your money and time because you are definitely considered late if not very late
Again, call the admissions up and see what they suggest
If you do really well, then you still have a shot, though it's slim. I took my DAT and applied in November, and I think my 30 RC was one of the only things that got my foot in the door for the final rounds of interviews. Though hey, it couldn't hurt to try either way.