If it looks like her picture, AbbyQuilts is right on all counts. :)
I would order the replacement bobbins from sew-classic.com, as well as the winder tire, felt rings, spool pins, light bulbs, cords, motors, plates and anything else you need. Jenny at sew-classic is just super at what she does and I always check with her first to see if she has what I need.
The class 15 bobbins you can buy at the fabric stores are sometimes not very good quality - but Jenny catches bad batches and sends them back to her vendors when she gets them. The stores don't have time to do that kind of quality check the way these small mom&pop businesses do. :)
She also has a downloadable manual for a Singer 15 on her site - might not be an exact match in the pictures, but I'd bet it'd be close enough. :)