Damian - heater core is about $40 from RockAuto. Changing it out isn't as big a drama as people make out but a shop is likely going to charge you the best part of a day in labour costs + the core cost. To do it yourself all you need is a socket set, a pair of pliers, a cordless screwdriver and a couple of bungy cords. It will take you a couple of hours to get the dash out the first time you do it, by the third time you can do it in about 45minutes. Its one of those jobs that looks hard and Youtube doesnt make it seem any easier, but when you actually do it turns out to be nowhere near as bad as people make out. Dont try removing the steering column you dont need to, just bungee the dash out of the way whilst you remove the HVAC box.
