'91 911 C2 Childseat ....... !?

Who knows where I can get a childseat that will fit the back of my '91 911 C2. The original Porsche 'Prins' is does not fit my car as my seatbelts are to short (!). Yes I could buy new seatbelts at $187 ex tax but maybe there's another sollution. Please help, I can't take my family out for a drive unless I take my Volvo 850....yackkk...

not sure what the seat config is like on the C2's, but I took the seat back out of my '83 SC and use a regular infant seat (14 wks.). This means my wife can't exactly sprawl out in front, but it works for trips around town. I have seen a seat that is sold in Europe for the 911, but it is not safety approved in the States...