How do you deal with a shower/tub combo with a wooden window to the outside in it?

The window was painted. The paint is cracking. It gets moldy, and I'm also afraid water will start leaking down the insides of the walls creating a severe mold problem. The shower has tile, which we plan to remove and replace with something else. A tub surround seems impossible unless we close up the window. Our house is brick, and finding matching brick might not be possible. Any suggestions would be greatly appreciated... Thanks!