Before you take it to a repair shop, remove the bottom plate and see if the gears are broken. They just get brittle with age. Some repair techs will tell you to put your money into a new machine, rather than have the gears replaced. The problem is, that when one breaks, they all will eventually break. They may break in 10 years, but they may break in 10 days. And there are 5 or 6 of them -- I can't remember what the vertical shaft gear is paired with. And they will probably charge $80 to $120 for each pair of gears replaced. Plus, you could probably find a replacement sewing machine (of the same caliber) at a thrift shop for $30 or less.
Having said all that, if the machine is dear to your heart, it may be worth fixing to you.