I currently have a Dell Studio XPS. I don't know the information on the motherboard or the power supply, nor how to find it (sorry). I am willing to track this information down to help out of course.
I'd rather not replace the power supply unless I have to, like if the new GPU reqiures a stronger one. I have no clue where to get started on a power supply let alone make it compatible with a new mobo.
I would like to overclock my CPU which is an Intel i7 920 at 2.67GHz which is why I need a new motherboard since you can't overclock Dells, but I don't want to overclock it to the point of needing a liquid cooling system (I don't feel advanced enough to put one in yet)
Also I discovered I will need a better power supply. I don't really mind what kind of power supply as long as it is as cheap as possible. I'm not exactly sure how much output it would need though, I assume this would be based on the motherboard I decide to get. I hope that info helps, I can provide any more that's needed.