Air conditioning

We have a sunroom that is poorly insulated and has big windows. The room is 21' x 14' and runs north to south. My wife eventually wants to tear it down and rebuild. I would rather use the room, and fix it up somewhat. The room has baseboard heat so that is fine. The air conditioning is more of a problem. There is an old built-in window unit (probably inefficient). A few years ago we had a Unico system put in on our first floor and they ran 3 ducts through the garage window. It tempers the summer heat a little, but not much for the afternoon sun.

The sunroom sits between the basement and first floor. Most people I have spoken to suggest a split system for the sunroom. Others think by possibly making the sunroom more of a regular room (smaller windows and insulation) I could keep the Unico system and perhaps add an extra outlet. A few have even suggested a window unit.

To keep the cost somewhat reasonable there are some options as to what I could do with the room. There is a flat roof, which I'm sure is not insulated. I could have insulation blown into it. I could insulate and re-sheetrock whatever walls possible. Obviously the big factor are the big, single pane windows.

In terms of air conditioning and re-modeling, I'm not certain what makes the most sense for this nearly 300 sq ft sunroom. Not certain if the split system, Unico or window unit would be best. Any advice would be appreciated.