Swee****er Creek Park does not have RV campsites.
There is Swee****er Valley Campground at Villa Rica, GA. About 45 minutes out on I-20. They charge $20 a night, or $100 a week for sites with electric and water. Dump station available. I've camped there many times, and have been storing my RV there in the field.
[edit] I live in Mableton, GA just west of Atlanta. I looked at all the campgrounds in the area when I bought my RV 3 years ago. The closest one I found that was decent enough to stay in was Swee****er Valley. The next closest I've been to is Chattahoochee Bend State Park. That is about an hour and 15 min out from the Foundry. At $23 per night or $161 per week.