You are hopefully aware that the coolit domino cannot have further blocks added to it. You may not want to be aware that the cheaper thermalright true or noctua coolers beat it on temperatures, especially with hot chips. What processor have you put it on?
You cannot get something analogous to the domino kit for a graphics card. The closest you could come is getting one of the kits designed to cool your cpu, and adding the graphics block (and possibly another radiator) to that loop. This will make the coolit domino look like an unwise purchase.
Water cooling is best done from components, much as assembling a computer is best done from components.