I found two Uno turbo engines up on Ebay, though I think one has already been mentioned by Neojames2k.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=10382&item=2484947510&rd=1
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=10382&item=2484936767&rd=1
Have to agree with you ChrisUnoman. Upgrade the suspension and brakes first before slotting a turbo engine in else it will be lethal!
Years ago I had a friend who dropped a 2 litre Ford Pinto into his mk2 Escort. His Escort was a 1.1 litre base model with DRUM brakes all round and no servo! We all told him to upgrade his brakes and suspension, but he wouldn't listen.
Off he went exploring all his new found power, then found out one day during some hard driving that with the extra speed and extra weight of the engine his brakes had overheated and faded and were all but useless. Just as a corner was coming up on a fast country lane.... Suffice to say he couldn't stop, skidded across the road and ended up on his roof in a ditch. He was ok, but the car was a write off.
After that he always upgraded his suspension and brakes before upgrading his engines....
It is surprising just how much better a car with uprated suspension and brakes can feel even with the standard engine. It will allow you to brake later and be more stable during cornering, hence maintaining a higher speed over a given distance. And it just makes the car that much nicer to drive too.