A friend of mine came to me with this very problem. She has one window to the side of her bed, and no other options for furniture placement. It was driving her nuts because she wanted symmetry. I completely understand about the desire for symmetry. Sometimes the chi feels off when things aren't just so. I get that, and deal with it a lot when combining elements in my own place.
But I am here to tell her...Embrace the one window! Sometimes things have more interest and character when they are less than perfect. In order to try and come up with some solutions I looked around the internet for some inspiration.
I particularly like the rooms where the window is dressed with a simple roman shade. I think keeping it simple is the best way to let it harmonize with the other elements in the room.
Finally I wanted to mock up a bedroom to really illustrate my point.