Paint the room a light nuetral color. Taupe is great. (It helps to bring out the natural color and highlights of the fabric. Especially if you put up a design wall to place squares.
The window....put a "window seat book case" under it. Then, position your sewing table in front of it coming out lengthwise (you'll be facing the right-hand wall when looking at pic.) This gives you the natural light when sewing and gives you space to extend your sewing area to the right of you machine when machine quilting. You can position your cutting board/ironing service (whatever kind) directly behing you against that wall. You can then just turn around while sewing and do you what you gotta do. Hang your other necessary supplies (thread, etc.) on the wall above this.
Place book selves (?) on their side for fabric stash, etc. on the right hand wall. Having them low provides you with the large wall area above them.
Just some thoughts. Hope this helps. Would love to have this space.
Last....."Have fun with it!!"