Welcome to the board and welcome to the world of vintage sewing machines!! I will tell you like this, they are like potato chips you can not have just one. I am fixing to hit the century mark with my collection and I do not see me stopping yet!
The machine is a Japanese 15 and you will see that it will become your all time favorite machine to use, I know that mine is. And the quality and tolerances are way better than the Singers. As far as the year it was made and by who (it is more than likely a badged machine) will be really fun to find out but maybe in a few years after I get a little deeper in my research we will be able to figure it all out.
If you want a manual for it just go to the Singer site here and download the free manual for the model 15.
http://www.singerco.com/accessories/manuals.html
Billy