It appears from your photo that there is not enough room to put the TV/frame over your new Fireplace unless you take off the existing mantel because it is too big. Correct? Therefore you would need to install a new, smaller profile mantel.

Can you post photos of all the walls? Really think it would look better if it were over a long console. The firebox is small and off center. Can't see the tv above it.

Something like this instead. Plus, gives a place to hide dvd player, movies, ect.

Traditional Home Theater · More Info