Very true, you have placed yourself in a not-so-good setup but two alternatives have to be tried, buy wall mounts for the surrounds (so that you can rotate and angle them) and fix the wall mounts as depicted by the Red or Blue on the back wall. Leave a distance of 20% of total height from the roof and fix the wall mounts at that point on the wall.
a) Turn the speakers so that they both face each other, shown by red arrows and tow them slightly towards the roof, this helps in creating a balanced soundstage. Listen to them for a week or so.
b) Direct the speakers towards the TV, straight, as depicted by the blue arrow, listen to them for a week.
Decide between the two.
The problem is that the fronts will directly hit the window, glass is a very good deflecter and will give you boomy sound.
Another problem is that there is no distance between your seating and back wall (I am assuming you will sit under the Aircon). There should be atleast 2ft or more distance for a better soundstage and to evade that boomy sound.
Best of luck, let us know the results.