This was the solution I was looking at last year...
Hmm; if it were me, here's what I would go with (would put you slightly over at a grand total of £334.82 or ~$529.02):
ASRock Z77 Extreme4 (£101.98) - http://www.amazon.co.uk/Z77-Extreme4-Mo
8GB G.Skill DDR3 Sniper (£44.21) - http://www.amazon.co.uk/G-Skill-PC3-149
Intel 3rd Generation Core i5-3570K CPU (£165.14) - http://www.amazon.co.uk/Intel-Generatio
Cooler Master Hyper 212 EVO (£23.49) - http://www.amazon.co.uk/Cooler-Master-H
The G.Skill RAM is recommended if you go with an ASRock motherboard--from what I've read, it's just more likely to work better than other brands of RAM