hey paololorenzo, we have the same ride! :D

water pumps need to replaced when ur car is still overheating even if theres no problem with ur radiator, radiator fan and the hoses.

compared to the alternator belt, the timing belt has a protective case (in most cars) which u have to remove to access the timing belt..in other words its hard. also when u replace it you have to check if its in proper timing. Your city is due for timing belt replacement. since you mentioned that it has already run 80t kms. as far as i can remember the oem bando timing belts sell for about 900-1200 per pc.

any competent shop can do this...try speedyfix..paging migz..