The Columbus stations are all about 20 miles from you, and are all on UHF, which will make this fairly easy. Replace what you have with a 4 bay UHF antenna aimed 225 degrees, as measured by your compass. You should install all new RG-6u coaxial cable to replace what is there, and be sure to ground the coax cable where it enters the house. If you plan to run multiple TV sets, you will need an amplified splitter like a Channel Master CM 341x, where x= the even number of TV sets that you will use.
Good 4 bay antennas include the Channel Master 4221HD, the Winegard HD-4400, the AntennasDirect DB-4 an the AntennaCraft U-4000
Here is a good installation guide:
http://manuals.solidsignal.com/AntInstallGuide.pdf