erm. I think seeing your grafic's card... you might want to consider adding a set together yourself.
I mean, the x1900's can put out a lot of heat, no? so I doubt the pump of a kit wich is for a CPU normally would be enough to cool the grafic's too. (ofcourse I could be wrong, I've never build a watercooling setup so far)
but I know there are special water blocks tor the 1900 series.
so my suggestion would be get one of those, get a CPU block with the same connection diameter. and then look into a good pump, reservoir and radiator, with the same sized connection. then you'd only need tubing, (and 2 T-connections for the tube, so CPU and GPU are each on their own circuit) and you should be good to go.