As a rule of thumb, a GPU is only overheating when it actually causes a problem. A relative temperature reading doesn’t mean too much if you haven’t had any stability issues when the system is under load.
When I first got my X1950 ATI card with the standard stock cooler, it would idle around 49oC, and whilst playing the likes of S.T.A.L.K.E.R. with HDR lighting, it would consistently stutter and then crash during certain stages of the game. The GPU was just about hot enough to cook eggs on... and 100oC isn’t uncommon with the high-end cards.
As such, 60oC - in all seriousness - is stone cold.
I ended up buying a Zalman VF-900 cooler and some Artic Silver compound and that made a massive difference. But I only went as far as that because the cooler that came with it was blatantly useless for the intended purpose. If your PC works fine, then all is well. Take those temp readings with a big pinch of salt.
Oh yeah, and PC World are great if you want to buy a generic
thing in a box, but that's as far as it goes most of the time. I bought a new monitor from them recently (helluva shiny it is too), but I wouldn't go in looking for honest advice