my guess would be, you would be playing at 25-33% of what the games graphics can offer.
This isn't too far different than my own.
I have better CPU and lower GPU than you, and the wattage seems low, but maybe I'm mistaken.
I currently run at most settings at low, draw distance 5, and texture filtering at standard, to help make the game look a bit better.
To show you what i see, here is a picture
RIGHT CLICK and hit view image, to see at full size, to get a better idea.
edit: keep most in game options off, and make it cap FpS at 30.
This way you can avoid spikes of lag.
Also if the game lags a bit, and FpS drop more than 30 (outside of town) try to lower the settings. it can be really bad for your PC if you strain it too much.