Replacing Noisy Fan on 9300

The right side (video card) fan has been noisy for months so I'm finally ready to replace it. It makes an intermittent grinding and vibrating noise so I guess it has a bad bearing or wear. How difficult is it to replace? I'm still under the complete care warranty but I'd rather do it myself than mess with shipping. Is there a better fan than the factory installed one? Should I replace anything else I while I have the case open? I was thinking about upgrading the CPU but if pc prices have dropped and performance has increased I guess it would be better to buy a new pc sooner or later.