Air Brake Antilock Control Unit/module problems of the 1998 Ford Windstar

On 12/7/01 my abs light came on and the trac off light started blinking. I took it into the inver grove Ford, mn and the diagnosis was broken wheel sensor and had to replace the ecu. That cost us $1600. 00. Then on 12/8/02, the 2 lights came on again. I called Ford very upset and was told that there is only a 12 month/12,000 miles warranty on the part. After another diagnostic test, it was determined the ecu again went out. Ford offered to pay $500. 00 of the $1147. 00 estimate, but it infuriates me that automobile companies can get away with this type of "highway robbery" and only warranty such an expensive piece for a short period of time. It is now a safety issue, because my anti-lock brakes do not work! what am I to do?.