like rhyso says your best bet is going to be the breakers,
i got a set of rear 256 MM brakes from;
V Dubs Ltd
(01732) 780111
London Road, Wrotham
Sevenoaks TN15 7RR
the other week, got a good price on them and i think they specialise in VAG salvage, there is also a VW specialist the unit down from them that might be able to give you a good price on fitting.
might also be worth getting a quote on how much for an engine transplant