I like your ideas and yes it's a pretty big project as you will have to also deal with the exterior of facade of the home. It will make a huge difference though.

Thank you! Do you know what type of professional I should contact for this project? We have never taken on a project like this so we are bit nervous! I am hoping to get the scale of the fireplace/windows correct so that it looks like it was always meant to be this way. We do have a set of sliding glass doors to the left so that will give us a lot of light as well.

Your wall is busy and does nothing for you. Before you spend lots of money : paint everything the color of your walls. Put doors on your shelves; the doors will hide all the stuff on the shelving; also remove the shelves over the side windows. These changes will simplify the whole look of your wall. Also please cover the light bulbs in your overhead fan; there are glass shades made just for this. Adding floor lamps or table lamps will also improve the look of your room .

I would have some stained glass in the arched window...

I would hire a designer in your city and have a plan before you hire a contractor. The designer will draw out the specifics and help pick finish materials. A contractor will then be able to give you a more accurate bid.

Below is an entertainment/fireplace area that we designed for a client. Notice the layout of the furniture and the shelving in the images.

High-End Residence · More Info

High-End Residence · More Info

If I were you, I would keep the fireplace off-center and the TV lower on the right side. How easy is it going to be to remove the upper window and matching the outside? If it is straight forward, that I would do it. Remove the columns, if they are just decorative. Simplify the book case. Maybe tile around the firebox.

Hang a large piece of art in the center or do a gallery of art.

Cover the window with something that looks like a shade. No need then yo maneuver the outside.