Vw have now stopped making them, tried to get some but after chasing round lots of dealers ended up getting some from ebay. So would always start there.
One of the best insurance companies i have come across is Volksworld insurance, I came across it at a vw show, They deal mostly with vws and will beat other companies.
I noticed LupoGTiNAB was selling bits from a gti a couple of weeks ago and all door cards were listed don't know if he's still got them, but worth a try.