check your local salvage yard. You can usually get a used one for around $20
unless it has the SRS device in it that pulls the seatbelt back when the
airbags go off.(I dont think that was available back then) Then they might
be a little more expensive. If you cant find one check
www.nordstromsauto.com. I checked it just now and they dont have one on hand
but they can probably get it if you leave your info.
As far as removing it, seat belts are not really difficult but they take a
TORX bit to get them out. Usually between a 45-55 size and I recommend using
a 1/2" ratchet to loosen it and put it back in. Otherwise it is pretty tough
to loosen with a 3/8 drive ratchet. Sometimes removing them will give you
access to untwist the belt as well. I have a 79 Delta 88 that I had to do
that with a while back and after untwisting it it is working like a champ
since. Good luck either way