If you still have the heater box in the car (ie no massive gaping hole behind the console) then this is easy.
You should have two copper/brass pipes sticking out through the firewall into the engine bay directly behind the head. You need to get hot water into one of these for your heater to work (and guess what, it comes back out the other pipe). Run some hose off the water outlet on the back of the head (it sticks out and turns 90degrees with the 2 temp sensors in it), run it into one of the heater pipes.
Then run some hose from the other heater pipe to the shotcock (thing in the engine bay that the heater cable goes to). And from the shotcock into somewhere that's connected to the bottom of your radiator.
Voila, hot air at the flick of a switch.
If there is no heater box in the car start crying, they are a bitch to get at and so installing one would suck. But once you have one just do the above.