Go to Scan they are cheaper and have better service from my experience.

Save some money and get this: http://www.scan.co.uk/products/550w-psu-...iet-fan-atx-v23

or

http://www.scan.co.uk/products/450w-psu-antec-basiq-vp450p-gb-80-pluseps-12vquiet-fan-atx-v23

You won't be able to upgrade that machine to use over 450w unless you replace most of the components and therefore it would make more sense to build a new pc. Which will mean you will need to reconfigure your psu requirements.

If he plans to do that by all means get a better PSU, I'd recommend this one, it's meant to be a very good modular PSU scoring highly for a great price: http://www.scan.co.uk/products/750w-ocz-...5-year-warranty

That will leave you with around £65 for a card...

For AMD I would say the Sapphire 6750, but as it is not in stock...http://www.scan.co.uk/products/2gb-msi-hd-6570-1334mhz-gddr3-gpu-650mhz-480-cores-d-sub-hdmi-dvi-d-low-profile-compatible

If you want to go Nvidia though

You can't really get a great Nvidia card for £60...but if I was limited to that budget - http://www.scan.co.uk/products/1gb-msi-g...dmi-low-profile

With graphics cards always look at the manufacturer too, as RMA procedures are quite important with Technology, try to stick with MSI/Gigabyte as they have the best reputations, Asus has good reputations elsewhere but let themselves down with their gpus and xfx/powercolor AVOID as their RMA is awful. Sapphire are ok.