What is the cost to have my thermostat replaced in my 2002 Audi A6 Quattro? on 2002 Audi A6 Quattro

I think it is the thermostat. The car overheated and there was pressure and steam at coolant cap so I think the water pump is working. The heater blew cold air after the car overheated.

Asked by for the 2002 Audi A6 Quattro
Big dollars , its hard to get at ..