Really need help with my Urraco!!

I drove the car to my mechanic yesterday.. We tested the car and tryed to find out what the terrible noises was.. We removed the oil from the gearbox and differential.. Found out it was bits of metal in the oil from the differential!! That explains the noises...

We haven't checked the inside of the differential and gearbox yet.. Does someone know where to find a new differential?? A used one could be as bad as my own.. I'm not sure to trust eurospares about this..
Does the urraco share the gearbox and differential with the jalpa? Does it fit?

You guys use GT Car Parts don't you? Could they have something like this?

This lseems to be quite expensive.. I was hoping to drive my urraco this summer, but seems like that could be difficult..

Anyone with some good advices?

Best regards from a very frustrated

Daniel

Norway