why a window treatment? there really is no room on the sides for a valance, a shade of any sort is going to impede the light and make the window look 'crowded'. There is enough going on without adding more. privacy isn't an issue so I'd leave it as is. If you want to change the color, then pick a shade you'd like. Maybe something more blue as Darzy stated.

I would suggest a creamy, antique white for the walls. To bring in some color you could go with a burnt orange color for the towels & shower curtain & on the window I would say either shutters or wood blinds.

Paint it a cream color to tie in the tile & it will contrast with trim. One color opens the space. Add window a roman shade in beige.