Have 1998 Audi A4 1.8T that won't start

Have 1998 Audi A4 1.8T that won't start, just shut off one day while driving, my dad thinks its the timing belt that broke, possibly caused damage to the head too? Looking for an idea what its worth if that were the case, its 124,999 miles on it, black leather interior, sunroof, 6 disc cd changer, heted seats, etc.   Also, anyone who would be willing to give me an idea what it would cost if we decided to have it fixed??