1996 Sierra - Coolant issue

I have a 96 Cutluss Sierra. Recently, the air conditioning stopped blowing as hard. When I popped the hood I noticed that there was no coolant. Filled her up and within 25 miles it was empty (obviously, since the car was overheating). I have checked and changed the oil - the coloring and consistancy was good. I climbed under the car last night and found that the hose that seems to be coming from the coolant container to have a seam that is open. I have a car book for my year and model, but it does not talk about hoses in association with the coolant. I can tell that there is a leak (I can watch it drip), but am not sure how to fix it. Can anyone give me some pointers? Thank you!

I would be glad to help if you can give me a little more information on where the leak is coming from. I can't seem to pinpoint it based on your previous description. Is it coming from the radiator, the coolant reservoir or is it coming from a small hose on the firewall of the car. To leak that much water that fast, I would have to believe the water is leaking from either the radiator or the heater core.