My baja bug has two seats, two seatbelts, but only one seatbelt buckle. Where should I go to get a second seatbelt buckle?

I'm not entirely sure what kind of seats are in the car, but they appear to be late '80s/early '90s Cavalier seats, in which case I'm looking for GM belts. The clasps are black, with a white button on the side.

Anywhere were I could find one online, or are there any good junkyards you recommend in the NYC metro area?