Might wanna check the warranty, example: Evga, you can take the heatsink off and replace the paste or the entire cooler. Warranty is still good as long as you can reassemble the card with factory cooler b4 sending it in.
One possible reason for what happened to your card would be dust built up in the heatsink/fan. I had an old 8600 GTS that I neglected to clean for a year or 2 when I noticed temps hitting 80c+, after blowing the dust out with compressed air temps dropped down to the 30-40c range.