mr2 cooling and heater system

hey road n track, how much roughly do u charge to bleed the cooling system? i have a 1990 gen2 turbo n recently replaced the thermostat, rad cap, temp sensor, cleaned the radiator, new water pump, checked headgasket and did a pressure test. As of right now the temp gauge sometimes rises to bout 3/4 then after afew seconds drops back down to half. i was told that is a classic symptom of air in the system. Also just found out that my heater is bypassed so how much roughly to get that working again? thanks