Floor Plans

I’m trying to rearrange my family room but I’m having some trouble. I really need an online site to help me to do this, kind of an online CAD or something. I want to put the furniture around to make it look like home theater seating but I can’t get the couch and chairs right.

It seems that there’s always at least one seating position that can’t see the TV. I know the room is odd-shaped. It’s long and narrow and there aren’t enough solid walls. I really need a better way to visualize this because moving furniture over and over is hard on the back. Any ideas about an online platform that does this?