Seat no longer will sit upright, gear wheel that raises and lowers popped out, may have snapped

I have a 1998 Volkswagen Cabrio GLS 4Cyl2.0L. the wheel that raises and lowers the back of the seat has come out. The small plastic interior part appears to have snapped. Is there a way to order a replacement part and replace this myself?

With a 14 year-old car, the probability of being able to order the appropriate parts from the mfr are…not good.
I suggest that you visit an auto recycler (what we used to call a junk yard), and see if you can obtain a seat from a late '90s VW.

Whether you choose to install the entire seat, or to cannibalize it for the necessary parts, I think that an auto recycler is likely to be your only solution.

My experience with purchasing piece-parts of preoprietary assembliesis that the manufacturers won’t generally sell them to you. I just went through that myself, where I research a wiring harness down to the connector part number…but the dealer’s parts guy showed me that the manufacturer lists it as a nonpurchasable part.

These are the situations where you learn how to innovate. It’s very possible that there’s a part in wither a parts store or a hardware store than can, with some modification, replace the broken part. But it’ll take looking with an open mind.

Good luck.

Like they’ve said, get a complete replacement used seat and swap it out. Go to www.car-part.com, see if they list one for you.

Along with @VDCDriver 's suggestion, you can often find parts for a car by just looking for the words “Parting out -your car name and model here-” on Craigslist.
Found a bunch of good stuff for cheap that way.