New build!

[Exteez]

Hello I would like to ask you guys for advice for me building a new PC. I would like to say that I have currently a £400 British pounds budget I can spend. I will give you my current spec's and I am asking for your advice guys what should I change etc - if I need to change/add RAM change motherboard etc. I just want you to basically build me the best PC for the £400 pounds keeping or throwing away any components you think are still useful to save money, or some which are garbage.

My current spec:

Operating System
Windows 7 Ultimate 64-bit SP1

CPU
AMD Athlon II X2 25
Regor 45nm Technology

RAM
4,00GB Single-Channel DDR3 @ 669MHz (9-9-9-20)

Motherboard
ASUSTeK Computer INC. M4A88T-M (AM3)

Graphics
Acer X193W (1440x900@60Hz)
ATI Radeon HD 4250 (ASUStek Computer Inc)

Storage
465GB Western Digital WDC WD5000AAKX-001CA0 ATA Device (SATA) 33 °C

Optical Drives
Optiarc DVD RW AD-5260S ATA Device

 

[EarthDog]

Power supply?

 

[Mandrake4565]

How about this? http://uk.pcpartpicker.com/p/77qRbv

 

[Exteez]

Power supply?

420W power supply

 

[Dlaw]

Make and model please, we need to know if it's quality.