Your original crankset should have been a Shimano Alivio, 24/32/42 teeth according to Bikepedia. Most likely square taper. If this is the case, pretty well any square taper mountain bike crank will fit.

You may not need to change the crank but just the chainrings. Count the number of bolts holding on the chainring and if needed the BCD (bolt circle diameter). Look for something that will fit. For example look at this chainring here and see if it will fit your cranks. You can increase or decrease the number of teeth within reason.