Interior architect/ help wantend with livingroom layout  

Decorate your living room in a ideal way !
Your home has enough space to accommodate your belongings properly. I suggest you, just keep sofas and other decorative things in main hall. In a living room,hang up the mirror right opposite to the lights as it helps in reflection. Use side tables instead of big racks.

The main room is being wasted
I'd put the sofa and easy chairs on an area rug in the main room, float sofa facing windows, acting as a divider between living & dining. Leave an open passageway along shorter wall, leading to small room.
Convert the area that currently holds sofa into an office/ playroom-- isolate all the kiddie stuff into that area, make main room a toy-free adult zone.
The floor lamp is in the worst possible place-- smack dab in the natural passageway from main room to smaller room. Wouldn't it be nicer if those walking from point A to point B weren't forced to make a detour... for the sake of a lamp?
Give that round dining table some breathing space(!)-- a round table shouldn't be crammed against a wall, you should be able to walk around it, be able to pull out chairs without hitting walls, etc.