I've got a Leadtek 6800gt agp graphics card. The card comes equipped with a giant heatsink/fan, but I've found that the fan is just not pushing that much air, it's a dinky little thing, plus it's starting to die out on me. I'm looking for suggestions on a good replacement heatsink/fan.

It's kind of rediculous cause the card's heatsink takes up an extra slot, so I thought it'd be a good overclocker, but turns out that the low-rpm fan kind of cancels out the heatsink. What I'd really like is just a replacement fan that can take advantage of the giant heatsink, but I'm not sure if that's possible. Is there a way to adjust the gpu fan speed in the gpu bios or anything?