To put it nicely, either leave the sun roof alone or have a good body shop patch in the hole. It is very hard to do this and come out with a smooth and even top. The headliner will also have to be replaced. There is the chance of finding another complete Mav and have them cut off the whole roof section and graft it to your car. Either way the cost is going to be a real bummer. Not knowing the condition of your car, maybe you could find another one you like and use this one for a donor car? Good luck either way.