Certain games like Elderscolls and Fallout ones sure. Games like BF:BC2 and Metro 2033, you might struggle. The Radeon 6850 would be a decent step up and well worth the extra money.
Its frequency is 2.4 GHz and it has a has a 2*4MB L2 cache.
I can't really afford an upgrade right now so I'm not looking for a replacement. I'd be more interested in overclocking it tbh, if my crappy power supply is up for it. I don't know much about hardware (I'm learning though) so I don't know about the power demands of CPUs. :shrug:
It's certainly showing its age these days, but overclock that svcker if your board is decent. The fine folks over at overclock.net can help you out in that regard. Plenty of guides and tutorials over there too if you search hard enough. An OCed Q6600 can manage quite well even today.
Power supply can be a factor though especially if it's a "crap" one. What you got?
As for the RAM, it was this http://www.ebuyer.com/product/166463 which has been discontinued, at least on that particular site.
I'm pretty sure you'll be just fine with this:
http://www.ebuyer.com/product/247673