I have a Dimension 4500 desktop and I recently upgraded the video card to a nVidia GeForce 6600GT replacing the video card it came with from the factory.  I get a message everytime I boot up that the new card does not have sufficient power.  I checked the specs and sure enough the new cards minimum power is 350w.  My Dell 4500's power supply is only 250w.  Can anyone recommend a good power supply ranging from 350w to 400w that I can use?  I don't want to cause damage to my motherboard, etc. by using this card with insufficient power.

Any help is appreciated.