Wow! Super lucky to have the luxury of extra space! I can't tell you what to do exactly with your space, but I would suggest to change out your garage door. I love this idea, and I would really like to utilize it when I build! If I can't have it...I'll just be happy that someone else is enjoying it in the meantime!

I'd suggest a shallow bench underneath the window and flank the windows with a base cabinet on one side and a desk on the other. Then open book shelves above the base cabinet and desk. I can't tell what the dark wall is on the one end. The steps need to curve from the door to the wall. A smallish sofa would be great for viewing a flat screne TV and a square table and 3 chairs up against the dark wall would be a great place for puzzles and games. Put a pendant over the table.

@spacelush, thanks for your comment :)

No windows big enough. You see we live in the attached apt of a very old house,which the bed would easily fit in. But I guess we could get the newer bed(king,wrought iron,our choice of colours+ it comes apart,not at all cheap! Just easier- but no cool top.,) Thanx Lyn,anyway! Every comment helps- now do you prefer an antique step stool or little stairs to get into a high-mattressed bed?