The Fiero Store cover isn't a match for the original. Theirs are best replaced as a full set for both sides. Usually the passenger side is the better of a pair, but the seat covers are interchangeable from side to side, so if you can find a drivers side, it can be installed on the passenger side.
There was a posting on Pennocks in the Mall section where someone had tons of seat covers. You might do a search there. I'll check also.