I had this done 3 years ago. I put in a double hung Marvin window 68x45, 8 over 12. It was pre-primed wood inside, aluminum clad, outside. They had to increase both the width and height of the window, this involving brick removal and patching afterward. The cost was $4200 - best money I ever spent - huge improvement. I had done the same thing in the LR a few years before. Upgraded the look of the whole house.
Q