The other elements of the room include a lot of space behind the couch and a garden room with large windows as you walk in the front. I'm not sure if there is a way to incorporate these elements for a livable room. Thank you.

That's a really great space you have. The area on the right side of the fireplace looks like it would be a terrific spot for a chair to read or stitch, etc. Is there a way you can create two seating areas, one near the fireplace and another facing the garden room?

I have much of the same space challenges that you do. I love the garden room. You may have too much furniture. Take everything out or push it aside and start with your rug. I'd move it a little closer to the fireplace. and then move the sofa closer too. You might want to visually line the back of it up with the edge of the garden wall...so as not to block the view into that room. I'd take out the little round table for now.
That garden room is where the eye will go to immediately. Is that the entrance? I'd make it the crown jewel of this cool space you have.

Great space.
You need one large scale piece of art or large flat screen tv centered on the wall over the fireplace.
Clean the space out as suggested above and find a great rug, Homegoods has an amazing selection reasonably priced. a small scale sectional would work on long wall and where current sofa is placed. A great one from Ikea with white slip cover would begin a light and airy feel. Your side table and coffee table would work with a sectional.
Behind the sofa I like the look of the 2 lamps and cabinet centered on the wall. Find 2 interesting print or stripe chairs to flank the table. Use minimal accessories- keep it clean simple and white/cream to create an airy space.

How wonderful that your father's home can be tailored to your taste! This inspiration photo has fireplace details almost identical to yours. I love the dark trim contrast and would suggest an L-shaped seating arrangement...sofa and loveseat or sectional. Treat the area behind the existing sofa as a secondary seating area as suggested by previous posters. A large bookshelf unit would be practical on that wall. The light filled garden room would be a lovely spot for informal dining and some wicker or rattan seating.