Window to Wall 1

The first project I'll work through here will be the one I just finished which was turning a window into a wall...and doing a better job of it than the last guy did.

In this picture I have already removed the wallpaper on the funny section of wall in the bathroom, the part I'm talking about is where you can see the brown paper from the drywall. There is a window off to the right, the window trim, and then a weird section of wall that sticks out down to the floor where the heater is attached to it. The window had a really weird sill that stuck out to the heater as well, about 3 ½ inches from the wall.