Unfortunatley Jill, these cars are “one-offs” and none of the manufacturers have been in business for years. For the most part, not much original MGTD interior parts fit them either.
Your best bet is to hire a good local auto upholstery shop and let them use what is left of your old stuff as patterns.
I recently built new wooden seat bottoms and a back. Then I bought two leather hides from Keleen Leathers (Chicago). I had a local guy fabricate new the new leather components 
seats using my old mildewed vinyl seat covers as patterns. He also fabricated new “map” pocketed door panels with the same leather hides.
I psoted a picture of the finished products which I still have not installed in the car. Frank will have to shrink it to fit here.
Installing new carpet in your VW based ride could be accomplished easily, the floors are flat, except for the tunnel. Keep in mind that VW Beetle stuff would not be direct fit and is very expensive from the “Bug” restoration houses.