DRG ARR, PIEDMONT FLT 467 WAS VECTORED FOR AN ILS RWY 36R APCH. AT 2001 CDT (APRX 7 MIN BFR LNDG), ALL ARRG FLTS WERE ADZD THE WX WAS (IN PART): 400' OVC, VIS 2 MI WITH LGT RAIN & FOG, WND FM 090 AT 8 KTS. RWY 5/32 WAS OUT-OF-SVC AT THAT TIME. FLT 467 WAS VECTORED FOR RGT TURNS (FM NORTH & WEST) ONTO FINAL APCH. AT 2002:42, THE ATC FINAL CTLR TOLD ANOTHER FLT (SAME FREQ) THAT THERE WAS A 20 TO 25 KT RGT X-WND ON FINAL APCH. WHEN FLT 467 WAS CLRD FOR LNDG AT 2005:36, THE SFCWND WAS RPRTD FM 100 DEG AT 4 KTS. THE ACFT WAS NOT CONFIGURED FOR LNDG UNTIL JUST BFR TCHDWN & THE COPLT DID NOT ALERT THE CAPT OF THE DEV. THE ACFT LNDD APRX 3200' FM THE THRESHOLD & THE CAPT WAS UNABLE TO STOP ON THE WET RWY. AFTER DEPG THE RWY, THE ACFT HIT AN ILS ANTENNA & A CULVERT, THEN WENT THRU A FENCE & STOPPED BESIDE RAILROAD TRACKS. RPRTDLY, THE CAPT ADDED 20 KTS TO APCH SPD FOR PSBL WND SHEAR & DELAYED SPOILER OPN AFTER TCHDWN. THERE WAS EVIDENCE OF HYDROPLANING & POOR FRICTIONAL QUALITY ON LAST 1500' OF RWY. THREE PAX RCVD BACK INJURIES; BOTH PLTS & 1 F/A HAD MINOR INJURIES.