You could get away with a 550W power supply, could be ample with an i5 paired up with something. Or 600W for future headroom.
XFX 550W
Thermaltake 600W
For £120 on a graphics card you could get a HD 7850, which is probably best bang for buck at the moment. Comes with free game deals if you look around too.
If that is too much you could look at the GTX 560 and GTX 560 Ti, they aren't the best graphics card, but they seem to do well at Directx 11.1 type games
GTX 570 are quite expensive, depends on much you want to spend on a graphics card and type of gaming, what resolution?
SSD wise I asked around about that and most people say 60GB is quite small, but if its going to be used mainly for office tools it'll be fine.
Sandisk Sanforce based (Cheapest)
Or Crucial M4 or Samsung 830/840 series Marvell (Faster, and more reliable range as far as controllers go at the moment)