I'd recommend changing the waterpump at the same time, i have done with all my previous cars, as only £20 and you wont have any probs with that side of the engine, many peolple in the past have reccomended this! Ant!
This ebay listing says it's for an Uno Turbo (amongst other variants). No idea if that's a good price, best bet phone a local motor factor shouldn't be difficult to get hold of.
http://cgi.ebay.co.uk/Water-Pump-Lancia-Prisma-delta-Fiat-Strada-Ritmo-Uno_W0QQitemZ260092979134QQihZ016QQcategoryZ31352QQrdZ1QQssPageNameZWD1VQQcmdZViewItem#ebayphotohosting