Replacing window glass yourself would be a bit of a pane, but stile, it's doable. I've tried to find out prices before, and I didn't find anything online, so start with the phone book and call around to glass companies and see if they'll sill you replacement glass in your size directly. I don't think it would be that expensive, so I would just hire it out unless I were in a jamb. I wouldn't be able to do a great job myself, but I guess it would be better than muntin. Just my own preference, but I would save up some sash for the job just in casing some other emergency comes along.
Our upstairs neighbors had some replaced, so I know it can be done.