Hi,
Windsor was made by National Sewing Machine Co. Yes, you can still get wearable parts for this though it's a little tougher than Singer parts. Needles are 20x1 or Boye (popular brand name) #14 and measure aproximatly 1-3/4". You can also scoot down the common 15x1 so the shuttle picks up the thread. Shuttles and bobbins are Boye #13. Always best to verify contents of these Boye wood tubes.
Here's a pic of Windsor and an interesting story. Personally, I think the fellers Windsor is worth what he paid for it.
Jon
http://lumberjocks.com/projects/67431