watercooling ain't worth it anyway, it's gonna cost you a lot to over do the air coolers you can get for way way cheaper. Suggestions? Post us some pics of the inside of your computer and ll the fans you have in it.
More fans, bigger fans, better fans, better cooling blocks, those are usually a good option.
I've added an extra cooler to my northbridge, as most asus boards run too high on NB temps when overclocking, changed a case fan on top of my case so that there was more air deplacement from out of my case. Next to that, I have a case fan in front of my pc, added one underneat my pc, got 2 at the back, one at the top and one at the side. Next to that, I got a different cooler on my cpu with a self chosen fan on it. Further more, I've pimped my graph card as well for the fan to run at higher rpm. I do have my computer overclocked and it's meant for that all. If you don't OC, you don't need that much. The new graphics cards are a lot better in temp management lately, you already see a big difference between my 3870x2 and a 4870.
The thing you could start with doing is getting a better airflow in your pc, replace some of the fans , ad some fans, some you've researched on the net with a high air deplacement. Other then that, a bit more expensive and a bit more work, you could buy a custom cooling block for your vid card and build some custom fans on it, mostly, that's a bitch of a task. Maybe better to do, get the coolblock that's on it off, put some arctic silver cool paste on it and place the coolblock back.
Sometimes, the idiots at the factories choose not to add cool paste at all

Or, just crappy cool paste.