Consider yourself lucky. I ran across someone yesterday with a gateway, same cpu as you and 180w psu.
I was going to tell the guy to add a video card, he would need to replace the power supply, but upon further review, I realized his motherboard didn't even have a pci-e slot. You could see the solder points on the board, but apparently they left it off to save 25 cents.
It Definitely Has A PCI-E Slot!
And While Choosing A PSU, Please Choose A Branded One Only. Like Corsair,Antec,Coolermaster,Gigabyte,FSP Saga II etc.
And Also Buy Those Which Are 80 PLUS Certified!(More Than 80% Perfomance Under Full Load)!