Some local searches will give you a boost based upon the address listed in your WHOIS record.
You will also want to get listed in Google maps for Atlanta.
Google lets you set a geographic target in Google Webmaster Tools, but you can only set it to a country level, so that's not going to help you on this site.
The last, and probably still best, option is good old-fashioned SEO. Create a page with Atlanta in the filename, title, h tags, etc...
Heck, Atlanta is big. You'll probably want to do another page just for the part of Atlanta you're in.