Was your graphics card in your PC at the time? If 'yes', I'd guess there may be water elsewhere in your PC too - and perhaps other damage. Wait until others come along to offer advice but, in your position, I'd remove the graphics card from your PC, dry off any visible water and put it in a bag of rice (this often works for mobile phones) in a warm place such that any moisture is absorbed by the rice. Leave it as long as you can. If there is any chance there is water elsewhere in your PC, the best I can suggest is to open up the case and blow air through it with a powerful fan - again, for as long as you can.
Unfortunately, if the system was 'live' when you spilled water on it, you may well have shorted something and it will be irreparable.