Typically with these type's of beers you have to go to the big beer stores. I haven't been in the Atlanta area in a long time so I don't know of any. Usually the small stores don't carry a very wide selection of imported beers. You might have to look around though.
You could also sent Spaten an email to find out from the distributor where you might find it in your area. SNA@spatennorthamerica.com
Have you tried th Tocco Hills Package Store? It is on the way to Virginia Highlands. Take North Druid Hills from Peachtree Rd and just continue until you see it in a large shopping center on the right. I'm at Oglethorpe University so i am pretty close to that area.