If you're applying to 20 schools, you should get in somewhere. Your GPA is below average, but DAT is solid. Having full time job should help you, but if you can get in any other EC's they'd be useful (like volunteering somewhere an hour or two a day after work?).
You're in good shape thanks to your DAT score. Be sure to thoroughly examine this thread (I'm sure you already have, but just in case you didn't). Cheers and good luck!