I'll assume that you have a newer Midget with the steering wheel lock.
This unit is held on with a saddle clamp around the steering column. The clamp bolts are special and generally cannot be removed with a standard wrench. They must be drilled out. If you can remove this unit, you will have to dissassemlbe it and remove the locking pin. The steeering lock is not really designed to be dissassembled, so this can be somewhat tricky. The replacement unit from Moss is pretty expensive too. You may find it's cheaper to get rid of the entire steering lock and replace it with a dash mounted "universal" key switch (available in most auto parts stores...but these do not exactly look very elegant if you're trying to keep the car original).
If you have not damaged the key cylinder unit too badly, it may be cheapest to have a locksmith come over and make a key for it.