Another photo

Maybe a few sets of these to make your wall window appear bigger;)

With such vibrant color on the wall, I would tend to stay neutral with the carpeting. A light tan, or oatmeal color would keep the room from feeling too dark.
For window treatments, how about a Roman Shade? I would mount it on the wall outside your window casing and make the shade at least 4" larger than your window all the way around, to make the window look larger. Or some floor-length drapes that again would make the window look larger.

A few mirrors in the room for reflection ,a bright colour for the curtains

There are a lot of good ideas here, and I believe it will come down to what tone you want to set in the room.
The hardwood floor idea definitely works for coordinating with the door, blinds and table seen in the photo. Going too dark on the stain would be something to avoid to prevent the room and decor from being monochromatic. The acoustics would change significantly with the sound reflection which can be adjusted for with an area rug helping to absorb some of the sound.
Anna's idea of a neutral carpet is a great idea to add brightness to the room. There are several carpets that incorporate woven designs to add character to a solid color carpet as well as several berber carpets that can incorporate additional tones to pick up the color of the wood stain.
There are a lot of good window treatment suggestions leaning toward fabric. Without seeing the rest of the room I would personally lean toward a wood shutter that coordinates with the door. Additional artwork or photos can have stain coordinated frames as well. If you want to illuminate the room a bit more a semi-opaque honeycomb shade would work well. The pleats would compliment the windows on the door quite nicely.
You may want to explore all of the ideas here and spend a day bringing sample pieces back to your home to see which look suits you the best.