The outside of the house is stucco. I had an installer over and he didn't think it was a good idea enlarging the opening.

Getting rid of one of the sidelites won't work either, then the opening will be too big.

Yes, I bought at home depot because I was tired of waiting for my window / door guy to come by. I've been trying to get his installer team to come out since December, still haven't fit me in. I had another installer come by and he's the one that said he doesn't recommend opening it up.

Cudaman - thanks for the info, the sidelites are fiberglass as well. I think I am going to have the opening expanded.