I just had that tank replaced by Red Devil up here with a later model one. Those ones are apparently prone to cracking, as yours show.
Assuming it is the plastic tank that has cracked
The tank cost $150. The labour for replacing that and lancing the radiator was $45. New Coolant that is apparently really good cost $50 for the 5 litres, but they do have a cheaper one.
Cheers and Regards Autosignature - removed when Minginator comes to Qld
Member - ATPS - Automatic Transmission Preservation Society