Is there a reason you have those colors on the walls? Without pics we are in the dark. What exactly is your style ?

Choose a contrasting color to the sofa, while choosing keep light requirement of room in view. So for that you should use light color curtains only, such as light golden, cream, Off-White.

Hi there! You can use beige tones- they go really well with brown if you add a hint of blue accent on. Also grey walls go well too (depends on the type of sofa you have- would be great if you can share pictures of your furniture here)!

you shouldn't use any dark color nor too much of light color. According to me, ash gray color would compliment the room but again that depends upon your color selection of your clothes.