Seems to be you could quite easily get rid of the computer closet. On either side of the fireplace it looks like you have some type of cabinet holding a bunch of books. All it would mean is getting a different type of cabinet that could handle a computer as well. I've seen plenty enough of those around. Such as this, http://www.ikea.com/ca/en/catalog/products/40180061

If you do that you could then centre the tv on the wall and move the couch to the opposite end maybe 10ft away with a chair against the wall.

I think it would work prety well!