Is it possible to put the sofa in front of the window and the loveseat parallel to it? Use either of those 2 tables from the 3rd photo as a coffee table. If it is possible to do this arrangement in the room you could add an area rug to define the space.
If there is space add some end tables with lamps or a floor lamp if there isn't enough room for end tables. The room seems a little dark.
Those 3 pictures are too small for that wall. If you want to keep them in the room you could hang them on the small wall that the mirror is leaning up against or take them out of the room. Hang the vertical one on top with the 2 horizontal ones underneath.
You could use that cabinet from the second picture against the wall where the 2 tables are for your stereo. If the stereo stays can it be put inside the cabinet? I would then take the other pieces: mirror, 2nd table and the mirror on the cabinet out of the room.
Add some colorful artwork. Pick a color from the art that you like and add some pillows and a throw on the sofa and loveseat.
You could add some drapery panels on the window.
Hope this helps.