Law enforcement, inlcuding prosecutors, will know that you had your first case dismissed for the fact that arrests will always show an a law enforcement criminal history, even if you have been granted expungement. You should consult with a lawyer for this case.
I work in the City of Marietta Municipal Court all the time. You should definitely look at the possibility of obtaining a lwayer on these charges. The Prosecutor in that jurisdiction can be reasonable at times. The charge is complicated by the prior Public Drunk charge potentially. When you speak with the lawyer you contact you need to know the specifics regarding that old case (when was it, what were the facts surrounding it, was the record expunged or was pre-trial diversion just completed without the record of the arrest being expunged). I qualified attorney in your area may be able to negotiate to a more favorable disposition in that court. You can find qualified attorneys in the Marietta area on this website: www.avvo.com. Good luck.