Was the computer powered on when the water spill happened?
Have you mistakenly turned it on since the water has been spilled on it? (Hopefully not)
Where else did the water spill? As I can't think of a situation where water could spill on the video card and no other component.
Have you tried drying the card out?
As far as getting official support in form of an RMA, the only option you have is to lie ,because they don't warranty irresponsibility. You have to keep in mind that if you do decide to be dishonest ,and tell them something else is wrong ,they'll be able to likely tell if you open that video card up ,or if it was damaged with water and is showing signs of it, at which point they're likely going to charge you for the shipping ,and you're going to get back your broken card.
What country are you in would also help because there's different laws in regards to "void if removed" stickers