Will my PSU be able to handle this video card?

I have the Hp pavilion p6644y, and it has a 250W power supply. I want to put in the Radeon HD 5570.

I know it recommends a 400W supply, but i was wondering if it REQUIRES that, and it will burn something out unless i have a better PSU. Has anyone even installed this card on a 250W psu?|||I've been using a 5570 on my computer at work for about a year now, it only has a 240 watt PSU, and I've had no problems. The TDP of the 5570 is only 39 watts. They really overstated the required PSU with this card.|||It won't damage the hardware even if you have a 700w power supply. It uses as much as it needs.