My husband was sweet enough to work on this when all I could do was sit there and tell him how to do it (I was still pregnant :)
He cut a pre-primed mdf board to fit the bottom of the window and added door/window casing around the edge of the window. We picked the same molding that frames all our doors for continuity.After finishing that up, we caulked all the edges and painted the whole thing in Swiss Coffee to match all the molding in our house. It turned out better than I was expecting and I LOVE it! The plan is to do this to all the windows in our house. Now that one is done, I'm hoping to get a window done a month until we're finished - but that's probably wishful thinking. We work much slower than that.
Here's a picture of the edge of the bottom molding. I had my husband cut it at 45 degrees and then straight for the bottom and I love how it looks.
Here's the before we painted and added the window framing and the after:
Our next molding project will be finishing up the crown molding and the mirror in the hall bathroom. I can hardly wait!