'flexible' budget (kind of) gaming rig...

sorry for the repost... some of the info was incorrect and im a noob to forums and i couldnt edit the message :3

hi... looking to build a half decent gaming rig, and the money and parts and whatever will be coming from my birthday   which is next month, and my budget for the actual comp is roughly £400 (can be stretched if there is a real increase in performance) and the screen is around £100 but im getting that from here (england) cause apparently they dont work form america because of the voltage?


here are the names of the parts ive thought about...

XFX HD 5830 Graphics Card
HD-583X-ZADA - 1GB XFX HD 5830, PCI-E 2.1 (x16), 4500MHz GDDR5, GPU 840MHz, 1120 Cores, DP/ 2xDL DVI-I/ HDMI
£90

PowerCool PWC-711 Terminator Midi Towe
PWC-711 - PowerCool Terminator Mid Tower with C/Reader High End Gaming Case w/o Psu
£40

AMD Phenom II X2 560 Dual Core Processor
HDZ560WFGMBOX - AMD Phenom II X2 560 Black Edition, Callisto Core, S AM3, 3.3GHz, 7MB Cache, HT 4000MHz, 80W, Retail
£78

Samsung Spinpoint F3 500GB Hard Drive - HDD
SATA 3Gb/s, 7200rpm, 16MB Cache, 8.9 ms, NCQ, OEM
£30

Asus M4A78LT-M AMD 760G AM3 Motherboard
Asus M4A78LT-M, AMD 760G, AM3, PCI-E 2.0 (x16), DDR3 1600/1800, SATA 3Gb/s RAID, Micro ATX, VGA
£45

Corsair Memory XMS3 6GB DDR3 1600 Mhz CAS 9 Triple Channel Desktop
TR3X6G1600C9 - 6GB (3x2GB) Corsair XMS3, DDR3 PC3-12800 (1600) Non-ECC Unbuffered, CAS 9-9-9-24, 1.65V
£55

Colours IT Black Edition CIT550UB 550W Power Supply (PSU)
550W Colours IT CIT550UB Black Edition, 120mm Silent Fan, Dual Rail, ATX v2.2
£24

Acer S221HQLbd Full HD 21.5" Monitor DVI/VGA
ET.WS1HE.008 - 21.5" Acer S221HQLbd LED Full HD Slim DVI/VGA 1920x1080 250cd/m2 12000000:1 5ms
£100

180mm Silverstone FN181-BL Blue LED Quiet Case Fan
180mm Silverstone FN181-BL Blue LED Quiet Case Fan
£12

sorry i couldnt put links here instead, for some reason they wouldnt work :s
thanks in advance