Tulane has the ACP program, in which you take gross anatomy with the MS1s. If you do better than the class average you're automatically accepted for the following year's class, and you'll be a TA for anatomy and physiology classes. If you're a little below the class average they'll still consider you. One of my lab partners got in this way. I don't know if they'll take you though; Tulane likes high MCAT scores, at least for their regular admissions.
I think your best bet will be to wait this cycle out. Take at least a semester of retakes, or maybe a summer and a semester, and apply next year to a good mix of DO schools. I think you should also consider studying some more for the MCAT and taking it again. You could try applying this cycle to a lot of low end DO schools, but even that might not get you in, and it probably isn't worth finding out. Retake your worst grades, bring your MCAT up by two points, and you'll be in excellent shape to go DO next year.