Looks like you have a gorgeous view out your window? Without knowing the exact floor plan of your room it's difficult to tell exactly what furniture placement would utilize the bet focal point, but your idea of two chairs sounds good. You want as much light as possible, particularly since your furniture is dark. Are you also working with a sofa which matches? Your ? about the art - love the colors BTW -
The art should not be larger than 2/3 of the wall space, with enough space surrounding it to give a decent representation of the actual wall. It's looks like a good proportion from what I can tell.