Do you not have heat or do you have the Brown Sludge problem?
If you just need to get heat. remove the two hoses going into the Heater Core.
THis kind of tool works well to break the seal.
After you get them off Shove a garden hose in the outlet and run it for a while. The stick it in the other side and do the same thing.
Make sure the problem isn't the blender door.
If you have the Brown sludge/coolant issue post back here and I will write the correct procedure up for you to eliminate it.
Mike