add built ins or bookcases to either side to shorten up the brick, and a new mantel... pehaps paint the brick a gray color. but it really depends on what you are doing with the walls and the floor first.

add a faux mantel that goes around the fireplace, and down to the hearth. put the tv over the FP and hide the cords, where the mantel will be, and then behind the built ins.

The brick looks like it is that color--not painted. I'd suggest painting it all white including grout. Paint the woodwork including the baseboards and molding white too. Paint over the paneling but not necessarily white.

If the bricks are painted you really don't want to get into stripping the paint--big, messy, stinky job.

Remove the mantel. Paint the whole thing white, especially that molding at the ceiling. Paint the surround black with high-heat paint. Add art and a plant. TV looks like it goes on the wall opposite the windows.

How large is your tv? If it is close in size to the firebox you will be able to mount it above the fireplace. Did you mean you want the mantle to only go over the firebox area? You should be able to find a fireplace surround at a fireplace specialty shop. It would come down in an upside down U shape around the firebox. I would go with a deep mantle. It should change the whole look of that wall. Please do not paint the brick, they look as though they have never been painted. In any case you should use a fireproof metal paint to paint the brass around the firebox to a flat black.