You should better go for a natural garden instead of an artificial one!! You really have a very good space to work on ! U can have a mdf wall panel (jaali work) like around 4'x8' installed on the main wall, lit artificially from the rear side. Then a row of planters sown at a ht of 2'.. then a l-shaped seater across it! If you need help in planning(charges applicable) leave a mail at archkrutistudio@gmail.com Something like the attached photo!

An uninspiring view of building next door was camaflouged with the help of lot of indoor plants -big and small in beautiful planters and other accessories. Stained glass birds sitting on a branch, colourfull bottles and metal butterflie fixed on glass panes made this sitout area very inviting.

Too many colors and dark colors make the space smaller also in your decor replace the printed cushion with a lighter shade of same blue. A small floral painting behind the sofa beside the window having rust,blue and cream on it will look good.Side tables on sides of the sofa should be there. Side tables of U shape whose Base can slide below the sofa side are available in market they will look great with your decor. You can put a small matching square table between the corner made by the handles of the sofa and put a small plant like mini bamboo on it. I hope my suggestions are of some use to you thanks

A typical partition or anything on the floor may make the space look constrained. I'd suggest you just use a different finish of flooring to partition the space...for e.g. you can have wooden flooring installed on top of the tiles in the area where the sofa is kept - to the human eye this will both partition the space as well as maintain the spaciousness.