Window to Wall 2

In this pic you can see that my curiosity got the best of me and I tore off the drywall revealing an old window hidden behind it. So apparently the windows were a pair but when they had the house stuccoed in 1973 and the 3rd floor made into a separate apartment they covered up one of the windows in what became the bathroom.
At first I was just going to cover it back up the way they did...but then Dan, the guy that made me a home repair professional, said to me, "In a perfect world you'd take all that (the window frame) out and put a couple of studs in there...but you and I don't live in a perfect world." Well...that's his funny way of saying what I should do but if I wanted to do it half assed I didn't have to do. I don't like half assed. I apparently live in a perfect world...So the next few postings will be the process of turning this window into a wall.