No extra FCC license is needed for an amateur radio service repeater, you can use your existing callsign. All classes except Novice can operate a repeater station.
Amateur radio has voluntary repeater frequency coordination. There is no legal requirement to coordinate your repeater frequencies but in the event of interference between repeaters the FCC usually will rule in favor of the repeater that followed the coordination process. Go to the Texas VHF-FM Society page for info on coordination.