You have _lots_ of signal. Take your indoor antenna up on the roof with a long, new cable and see what you get. Aside from the trees, you should not need a lot of antenna to get everything from Atlanta (233 magnetic). WXIA likely won't come in without a VHF antenna; there are plenty of UHF-VHF antennas on the market, like the Antennacraft HBU series.
http://www.antennacraft.net/Antennas/AntennasHBU.html An ANT751 pointed at 209 magnetic may be all you need, if there are no obstructions to the horizon.
http://www.amazon.com/RCA-ANT751-Dur.../dp/B0024R4B5C