Looking for new Graphics card and Power supply

I am looking to get a new graphics card for my computer because atm it has integrated graphics, which as most of you know sucks. The power supply is 250W which I doubt would be enough to have a whole new graphics card implemented. The model is p6166f. The mother board has this for a graphics card slot PCI express 16x GPU. Please give me suggestions, I am looking to spend approximately 150 - 200 $ total.