Can you pare down the items on the mantle and locate the round glass dining table & dining chairs over by the windows?

Add a painting on the fireplace wall in line with the glass dining table. Make that a dining space. Even add a round area rug underneath the space to further define the area.

One idea is to spread out the living area further away from just the fireplace. If you add a bookcase or tall cabinets to the left of the fireplace, and pull the love seat closer to the windows, it would make this area larger. To enclose the reading area more you could place another large upholstered armchair or recliner next to the bookcase. Adding a large square coffee table or ottoman between the two couches would help tie the seating together.

your fireplace position reminds me of this bloggers fireplace and their room make-over: http://jennasuedesign.blogspot.com/2014/10/the-big-living-room-reveal.html

Can you show a photo of other side or the rooms? Use a small game table & 4 slide around club chairs in the area next to the windows. How big is your dining table?