The room looks like it’s about the same size as mine, though your room is a lot taller than mine.
I’m not sure there’s an IKEA around, but I guess there’s something similar somewhere around you. I bought a 2m worth of roll up blinds for the one (huge) window in my office. It cost me only $55 and completely shuts the light out. Well spent money, and gave a totally new mood to the room. It feels “professional” when you enter the room.
Now my only problems is arrangement. Where do I put the sofa? Where do I put my work desk? Shall I rather have chairs for the clients and toss the sofa?
Limited space means limited options.