Need help in deciding right psu for my graphics card

Hello all members,
I have bought a PowerColor AMD/ATI Radeon HD5670 1 GB DDR3 Graphics Card recently configured with
Core 2 Duo e7500 processor
Intel DG31PR motherboard
2+2gb transcend gb ddr2 ram
hitachi 500gb sata Hard disk
acer p195hq monitor 1366 by 768

So,Which PSU should be enough at reasonable cost?

Please suggest,

Thanking you,