You can do it yourself--I did.  My carbine stock had a cheap canvas sling and non-inletted swivels which I junked immediately after acquiring the gun.  I simply made tapered plugs from some walnut scraps, squeezed a little Elmer's into the holes, and tapped the plugs in.  Once the glue dries you can trim off the excess with a chisel or sharp knife.  Not perfect, but unless your stock is museum quality, it's not bad.  Now if your stock has inletted swivels, it will require more work--fitting wood pieces the shape of the inletting, etc., and the result may not be to your liking.

Where are you located?  Find someone near you who has experience, and hopefully, they can give you a hand.  I'm in southeastern Michigan!