Replacement forks are not expensive, just make sure you get one for a 27" wheel, not for a 700c wheel. Also make sure it has the right steerer tube length (the bit that goes up through the front of the frame). If you cant get one in a bike shop try your local garbage bins. In those days they made forks so they would bend before the frame, so a crash would result in a cheap fork replacement rather than an expensive frame.