Which lens for my nikon d40x?

I am primarily interested in portrait photography and already have the 35mm 18-55 lens. I am just not satisfied with it for the kind of pictures I take. I have been looking at the nikon 50mm f1.8d and the nikon 85mm f1.8. I'm really bad with camera lingo though... what would be the real difference in these lenses, and are they the right choice? Thanks for the input!