Can you post pictures of your machine and cabinet? That might help us guide you in your restoration.
Woodwork can be prohibitively expensive to have restored, that's why many of us do the work ourselves. I wouldn't shoot for "brand new" either. The machine earned any wear to her bed or pin rash on her arm from honest use by your husband's grandmother. I would be inclined to simply clean the machine with sewing machine oil, free it up if it's stuck from sitting for years and put it back to work.
If you're not comfortable restoring the woodwork yourself, you might try a local college with a woodworking department and see if any of the students there want an extra project. Another option is an antiques restorer but prices can be a bit shocking.
Rodney