Get sorted as soon as.....belt + thermo + coolant and see how it goes as dub said its a solid little engine so chances are you mabe ok after that if its still taking in water (and its not leaking from anywhere) + the temp is high you can only assume its the head (while doing this job you may aswell do the water pump) if its physically leaking it would be from the water pump, rad, thermo stat housing, heater matrix and hoses.