A new solid color area rug, larger lamp and maybe a coffee table ?

Throw pillows in the colors of
your art work would be pretty too.

Keeping/replacing what?

Four kids under 10! First, Move the love seat so the right side of the L/seat is in front of the side table creating a corner. If you have a baby in diapers, (I see wipes left out, ) ...get a basket with a handle and put in wipes, diapers and baby powder or whatever you need for that diaper change and keep it handy but hide it. Get a laundry basket for your laundry and not use the L/R sofa. Keeping clutter to a minimum is key. You can buy storage cubes to be used as a coffee table and storage for toys, books, whatever. If you have a lot of toys, I suggest you get clear Rubbermaid containers and line the room with them to hold all the toys. At least 6 throw pillows in either gold or rust or both and put on the sofa and L/seat. Push back the blue chair to form a conversation pit. Hope this gives you a place to begin.

Other views of the room.