"Gewehrfabrik" just means "rifle factory." It should also have a name saying whose rifle factory. There have been hundreds of thousands of .22 rifles made in Germany, by probably a hundred or more makers.
Good pictures would help, or a least a better description. I don't hold out much hope for parts, though, since most of those guns were never imported and have long been out of production. If you provide pics and just what parts you need, maybe someone can help.