Yes, look to get some window treatments, nice heavy drapes of some nature should work well. What you want to do is cut down on the reflective surfaces that your sound bounces off of. Yes, you can go too far here and actually overdamp the room but you have to go a long way to do that. Have you ever given thought to using a subwoofer? Reason for this suggestion is that you could pull the speakers a bit further apart while not limiting or excluding the lower frequencies as they would be covered by the sub. Also using the sub would allow you to direct the lower portion to the sub releaving the burden on the L&R speakers freeing them up to do what they do well, produce the mids and highs, just a thought.
Overall when looking at the system the first thing that comes to mind is speaker placement. It seems that the speakers are kind of out on their own and in the one picture it seems that the side wall may be causing you some boundary gain issues. Do you have the ability to move the system elsewhare in the room? As odd as it may sound I would be tempted to place the flat screen on the rear wall and the speakers as well, of course moving them out a foot or more but the rear wall willl act to your benefit and generally get the speakers out of the way. The other suggestion would be room acoustics, there seems to be many flat untreated wall surfaces, try a large area rur and some soft wall hangings, stay away from pictures with glass as this will not assist. Components selection is solid but until you play around with the actual set up/ placement you are really never hearing all that you paid for. Best of luck.
