2008,A/c not heating

Hi there, i have a crown hybrid with 2grfse3500cc engine. My a/c is not heating but when i refill my antifreeze by radiator cap it works fine. Antifreeze that i refilled is leaking by coolant reservoir. And when i open radiator cap it blows coolant and bubbling. So i thought it might be thermostat is not working. And i changed it and also radiator cap. But its still not working properly. What other reasons might it be? And i checked my oil cap but it was fine, cause i thought it might be head gasket is blown
My car has an automatic transmission.