sounds like a leak in matrix pipes, you will need to have this fixed when you have sometime spare, get replacement cheap from good scrappy, details of how to change matrix in haynes manual (halfords, motor factors etc) keep an eye on water level, but should be ok to use car until fixed as long as you dont mind being cold in winter, and having to keep windscreen de-misted by hand. also be careful with water spraying inside car, not good for your electrics.
hope it helps
September 2010