have you tried the dealer?
IIRC, when i was last in my local dealers they priced (approx.):-
cambelt £30
tensioner £40
water pump £40, but i got the water pump from my local motor factors for £34
make sure the water pump has a metal impellor, as the SEAT version has a plastic impellor
which can break and IIRC failed after only 16k miles on Muddyboots' car!
a quick search will give you all the info you need mate