I have what looks like the same machine! I believe it is called "The Rocketeer" and it is the last all metal model made. Mine is missing the foot pedal/power cord, but I've found some online and just need to make the purchase. Here are some links you might enjoy looking at:
http://www.singer500a.info/
http://aliciajeanae.blogspot.com/200...rocketeer.html
http://www.flickr.com/groups/606891@N22/