Hey Deb, welcome to the board!
If you can post a photo we can probably be of more assistance but National made sewing machines over a very long period of time.
But in the meantime here is a few links to keep you out of trouble...
National History:
http://www.ismacs.net/national/home.html
National History:
http://needlebar.org/nbwiki/index.ph...achine_Company
The National Photo Album:
http://needlebar.org/cm~nb/thumbnails.php?album=516