I see you certified through Sea Ventures. It's probably a common name, but I know there's one near Holcomb Bridge in the Norcross area. If that's the one you used you're in the neighborhood. There is a pretty active local diving community. Lanier has not been that good in the last year or so due to the drought leading to decreased access (read mud) and decreased visibility. However there are a few other places. Dive Haven in White, GA has been relatively decent this year although there isn't that much to see for new/rec divers. 2.5-3 hours drive puts you in range of a number of other dive locations such as Jocassee, Loch Low-Minn, and Alabama Blue Water (I'll be there on Sat) - all better than Lanier by far.
Lanier's best diving is during the colder months of the year, as are pretty much all lakes and quarries. For Lanier this means after the winter turn over, which happens generally in the first part of December I think, on into April or even May.
All local diving is cold below the thermocline. Most places can rent you a thicker wetsuit (or even a dry suit some places) if you don't have one but you can pick one up pretty cheaply.
It seems like there are generally scuba board people heading to the springs monthly during the warmer months. Also some of the shops do. Check with Divers Supply in Marietta or Doraville for example.
A group of us are heading to Vortex/Morrison/? that weekend so we'll be in the area and it might be possible to hook up, don't know where you are staying. I think our plan is to camp at Vortex. Have you checked the tides, what days/times are going to be good for a shore dive in that area?
