how much is a blown Head gasket for a 2004 oldsmobile alero V6. on 2004 Oldsmobile Alero

my car keeps running hot and cutting off on me i got a new thermostat put on but its still doing the samething plus smoking from the back pipes.

Asked by for the 2004 Oldsmobile Alero
have a chemical test done on cooling system to ck for exh gases in cooling system