Follow-Up:
Hi: I have an 87 and the fuel filter is located just behind (i.e. toward the rear of the Rialta) the engine. It's relatively easy to replace though only if you have ramps. Any VW dealer will order the filter for you - I got mine in a day. It comes with new hose clamps as well. It'll be good if you have a pair of golf tees to use as temporary plugs for the in/out fuel hoses when you're working . It's no fun, dangerous, and quite unnerving when you're squirting gas all over the driveway even less on yourself when doing this pretty straightforward task. Hope this solves part of your problem.