Ok I have a 01 Saxo VTR, tonight my temp guage went up and the red light come on, I stopped my car and had alook at the water in the exspansion tank ( think thats right ) and it was empty. So I knocked on a random persons house and asked to borrow a kettel of water ! Once refiled I continued on to my girlfriends house, I had reachers her's I checked again and noticed it had gone down by atleast a quarter. Within the hour it was completely empty again.
Now on the front shelf just infront of the cooling fan it was soaked with water, although when checking on the floor I couldn't see any exsess water ( although it had been raining

) what could this be ?
Is the radiator runined ? or is it the pipes or could it be anything else like the water pump ?
Im not to worrid about it as I have a dealer warrinty with SEAT and that covers parts and labour and me car is completely unmodded so it should be fine, but would just like peoples opinons on the matter. Thanks for your help !