Building/Buying a new PC for WoW HELP!!!Follow

Hey guys, my new system works amazing with WoW no lag at all.

1gb Ram
3.0ghz processor

XFX GeForce 6600GT 128MB DDR3 AGP 8x (which is wicked fast, better than ALOT
of 256mb)
Memory Type
DDRIII
Memory Bus
128-bit
GPU Clock Speed: 500 MHz
Memory Clock Speed: 1 GHz
Graphics Core
256-bit

Its better than my old 9250 256mb radeon anyway.

Ok getting down to business, Im giving this PC to my brother.
And i have about £600-700 to buy a new one im pretty sure I could get a far better one than i currently have.

Maybe some of you have some good websites that sell quality gaming PCs?

Im looking to build a PC but I dont no where to get the parts, if I did start to build one I would most likely use the same graphics card as I have now
since its good and WoW needs a fast graphic card

I dont lag in End game instances like Naxx and AQ40.

So if you can find one that will give me NO hastle with WoW and will run smooth on max graphics and do everything i want it to without any annoyance, that would be grate.