VERY small room, very bizarre charachteristics

I am moving to a new apartment which we have just bought and I will be setting up a room to use for mixing the short film scores that I do as well as recording electronic music. I am going to buy a set of speakers once I move in but don't want to spend too much money. My main question is that the room is quite small - 9'11 x 7' x 12' (ceiling). I think the ceiling is either 11 or 12 feet. I cannot tell yet but have included a picture of the layout. I also dont think i will be able to pput up any permanent traps etc so i was wondering what i could do with my rough layout to make sure i get the best response. The layout i have attached is what i am planning. i haven't included any trap ideas, mainly because i just dont know. As you can see, the door and the window are in wierd positions. Is there any such thing as un-obtrusive traps. I am also trying to keep the wife happy that I am not ruining a room in our new home! The old catch 22. I would also envisage a filing cabinet in the bottom right corner by the door. Other that that, my Yamaha P50 midi keyboard along the right hand wall.