http://www.techpowerup.com/printarticle.php?id=134
^How to apply thermal paste to a cpu..basically the same as GPU.
http://www.frozencpu.com/scan/se=Sys...nu_search.html
^Aftermarket GPU coolers.
A good thing to try is to buy a new GPU cooler, then apply thermal paste to the new cooler and attach it to the GPU. Im still not sold on those temperatures being accurate though...
Edit: I just now noticed that your card is overclocked a decent amount. 400/980 is the original speeds and your a decent amount above that at 560mhz/1.08ghz. If you can only run games half settings or they crash, you need to lower your overclock and check the stability.