If it requires a bunch of machine shop work it could get quite costly and it will be based on if it ran without adequate lubrication for any length of time. Problem is you will want to go ahead and change the flex joints and maybe the center support bearing while you have the driveshaft down. I'm not sure of cost in your area but I imagine it would be easy to drop a grand into a differential/driveshaft rebuild. Try to find a good independent in the area if you don't want to do it yourself. You will probably still need a good machine shop even if you remove/replace yourself. The manual that shows the differntial rebuild has some specific machine shop work detailed in it.
Have you checked on the forum for recommended shops in the area.

__________________
Jim