ACR MLG WRONG RWY APCH AT MCO.

Narrative

WE WERE BEING VECTORED FOR AN ILS TO RWY 17 AT MCO; HDG 100 DEG AT 5000 FT APPROX 10 MI N OF THE ARPT. APCH POINTED OUT A WDB WE WOULD BE PASSING OVER AND ASKED IF WE HAD EITHER THE WDB OR THE ARPT IN SIGHT. I HAD THE IMPRESSION AT THE TIME WE WERE GOING TO FOLLOW THE WDB TO 17. WE WERE IN AND OUT OF SCATTERED CLOUDS AND SAID WE HAD NEITHER AND ASKED FOR LOWER BECAUSE WE WERE APPROX 2500 FT ABOVE THE GS INTERCEPT. WE GOT BEYOND THE CLOUDS AND RPTED THE WDB AND THE ARPT IN SIGHT AND WERE CLRED FOR THE VISUAL TO 17. I FLEW THROUGH THE 17 LOC TO LOSE ALT; AND KEPT THE WDB IN SIGHT WHO I THOUGHT WAS GOING TO 17 AND FOLLOWED HIM. THE FLT GUIDANCE PANEL HAD INDICATED LOC CAP WITH FULL GS DEFLECTION; AND SOMEWHERE AFTER A NUMBER OF HDG UPDATES WERE MADE; CAPTURE DROPPED OUT. THE GEAR WAS LOWERED AND LNDG FLAPS WERE SELECTED TO ASSIST OUR DSCNT. WE FINALLY GOT ON GS ABOUT 5 MI OUT AND NOTICED LOC DEFLECTION AND REALIZED WE WERE HEADED FOR RWY 18 AND THE TWR ADVISED US TO HEAD BACK TOWARD 17. WORKLOAD WAS VERY HIGH; AND WAS MADE MORE SO BY ATC LEAVING US SO HIGH SO CLOSE IN AT 80 DEGS TO THE FINAL APCH HDG.