You could just give specific's such as size, view, bathroom attached, walk-in closet, color, window coverings, etc.
I've seen many ads on internet sites stating their ad's just like that with an explanation that the roomate has not moved out yet. You could have prospective tenants come and view the rest of the apartment & amenities.
It would be easier to just wait it out so there's less hostility with your current roomate. It's only a few days til the end of the month.
Good luck with your difficult situation!