Lawrenceville Auto Parts should be reasonably close to you.
Mahdavi should be really close to you.
Dynolab (Marietta) is farther but is good if you are on the other side of town.

Many, many places in Atlanta to get refills.

A wet shot shoots both fuel and nitrous into the engine, a dry kit relys on your existing injectors to put in enough fuel.

Start with a simple dry fogger shot, just it small to start (30-50), take the timing down 2 degrees for each 50 shot. Use jsut the minimum you need to make the desired power. Don't get carried away with it.