You have to apply to the Governor of GA. You should contact an attorney in GA that has handled such petitions previously. Also, your felony shouldn't prevent you from getting a passport, however, some other countries have the right to keep you out if they don't like your record. If you were formally convicted, your chances of getting your civil rights restored goes down. And, how much time has gone by since the offense is usually what the they look at too.
I would advise you to contact the Clerk of Court for the county where you were sentenced because they may be able to provide you with the necessary paperwork. Any attorney licensed in Geogia might be able to assist you moving along the process in the most expeditious manner. Ultimately the process goes through the Governors office which can take a long time.