PSU for ATI All-in-Wonder HD

I will be adding a ATI All-in-Wonder HD to a Dell Vostro 220.

The Vostro comes with a 300W PSU(Link to Service Manual), but ATI requires min 400w ... Could someone make a recommendation of a quality, inexpensive PSU?

Specs: The Desktop unit has:
Processor: Intel Core 2 Duo Processor E7300 (2.66GHz, 3M, 1066MHz FSB)
2 GB DDR2 Non-ECC SDRAM 800MHz (2 DIMMs)
250 GB SATA Hard Drive (7200 RPM)
16X DVD +/- RW w/dbl layer write capability
Integrated Intel Graphics Media Accelerator X4500HD
Stock Processor Cooling Fan, Plus three additional 4" cooling fans.

Usage
The Vostro 220, will output via All-in-Wonder HD, DVD Movies, PowerPoint, Television, Internet, and audio to two 32" LCD Tv's, one 6' away, the second is 75' away; it will also be used to output to an InFocus video projector via 75' VGA cable.