Major coolant leak--how much is this gonna cost me?

[frosty]

Car: 1990 190E 2.6 with approx. 104k miles.

Okay, here is a classic case of putting something off and letting a potential problem become an actual problem. No need to tell me--I know. I think about half a year ago I noticed that the upper or lower radiator hose (forget which one, but it connects to the thermostat) had a very disturbing bubble at the end that connects to the thermostat housing, right above the hose clamp. I decided to have it checked out at a later time and continued to drive the car. Fastforward. A month earlier I had been a bit more concerned about this bubble, knowing full well that it could burst soon, but the fact that I had been able to drive the car without any incident made me put off replacing the hose a bit longer! Well, guess what? Today I noticed that there was a leak of something under my car, not a puddle, but definitely a leak. I opened the hood and there is a very pin-size hole on the bubble. The strange thing is that the resevoir was almost empty, about 2 inches of fluid in the resevoir. There seems to be no overspray of coolant in the engine, as I would imagine a hole in the coolant hose would do. The car had been sitting for months and was only used two days ago for a night out. No idiot lights came on and the temp. guage, if I recall, was normal. I suspect that night of driving (approx. 10 miles total) was when the bubble finally ruptured, though not castastrophically.

Anyway, I did an archive search, and my heart sunk. Could all this coolant lost be the water pump, which I've read is an *gulp* expensive repair? Yes, the coolant seems to be seeping out from the belly pan on the driver's side! The top of the engine is clean, but I can't look under the engine to confirm if much of the leak is coming from another source. I'm just hoping it's just the coolant hose, but can a tiny hole cause that much coolant to leak? Grrrrrr.

Sorry about the long post. Please help!