lol, that's a big card your putting into a factory computer. I don't think it will but if it does pull it you will run the risk of it going out and taking some hardware with it. This is something not even to think about doing. The card is probably going to pull another 60 walts out of the system.

http://www.jscustompcs.com/power_supply/

Might help some, select the cpu type at the bottom.
I hope this is something you have been thinking about, and not going to jump into this. If your one of those that keep your case in a small hole with little airflow your going to have to change this fast. Hope you have more then a factory heat-sink also.

Have fun