Advice needed about GPA and DAT. PLZ...

Hi, guys.
1 really want to know possibilties. I applied to dental schools last year, and I haven't got any acceptance letter. I think i failed to get into the dental programs this year. I contacted a few schools admission office and asked why I was rejected. They said my GPA is low and recommended me to take some graduate course or get MS instead and then reapply. In fact, my GPA was overall 3.02 and 2.89 science. Majored in biology. (Disaster was my freshman and sophormore year(GPA 2.6) and since junior I been in Dean's list. GPA was 3.7) I have 14 science repeated course which brings my GPA down dramatically. I have worked as a dental assistance and have about 5000 hrs dental experience. Some vounteer job participated.

My DAT was
PAT 24
Bio 20
GC 19
OC 19
QR 17
RC 17
TS 19
AS 18
I took last october.

If I take it within 2 or 3 months and get around 21 or 23 something like high score, would I be able to have a good chance to get in for incoming cycle? If I apply to some schools in midwest? Because I really want to save money. Ms or post-bac requires me to pay at least $30000 per year. Anyone can answer me to resolve my issue? I have been frustrated because of my GPA which I screwed at first two years.
Plz, gimme some advice.

Thanks.