Walleye are more widespread than they ever have been in GA. I'll just hit some high points and you can send me an email for more specific (if needed). I caught the original lake record Walleye in Lake Russel - a lake they thought did not have Walleye. It has since been beat twice and the latest is the state record Walleye. My 7lb 4oz fish was in April on a spinnerbait, during a bass tournament. My brother had one as well that went 5.5 lbs. This was post spawn on a main lake hump in Beaverdam creek.
Last year there was some buzz surrounding the Walleye population in Lake Sidney Lanier. It did not surprise me because we'd caught small ones in two different locations - both down lake (Young Deer) and up lake (Holly Park). The new info on Walleye is available on the GA DNR website. If you can't find it email me and I'll send you a copy. As you can imaging the spawn happpens really early while the water is still cold. One are they pointed out for this spawning activity is a "Mud Creek" that is somewhere above Lula Bridge up the 'Hooch. Size was up to 7 pounds.
BTW - you can also catch Yellow Perch in Lanier