1999 Ford Escort Heater Stop Working Suddenly.

Hey Guys, great site. But To the point is that I've had my car for almost 10 years now and never had a problem with it, but last week My Heater just died on me on my way to work. I do feel it blowing very very litte, and my defrost for my back window works fine. I did check my radiator lines, they are fine, but one of the tubes has a green crust around it, and you can see their is a little leak of anti-freeze that drips, but as I said it is very little. I don't now what else to do, and am Sure if I take it to Ford am going to lose an Arm and a Leg paying for a repair that coould have been done spending less then 10 dollars. So Guys can you help me or tell me what steps to follow to check my heater, I live in Virginia and it's an Avg. Of 40. F over here so blankets and big coats only works so much for so long.