I agree that Sew Classic is a good source. Your other good choice is Stitches-in-Time (Cindy Peters) and you can find her shop at eBay. If the walking foot is not listed there, she can get it for you. She is excellent, fair, good service, good prices, knowledgeable.
I also have a Singer 201 hand crank, and the thing I like it for most is thread painting. I can get incredible precision. Here is a huge warning for you, and necessary with any all-time-top-ranked Singer 201 machine: HOLD your thread tales ALWAYS and use a starter scrap with he first four or five stitches it in before starting on your regular fabric (leave it attached and sew on air for a stitch or two between fabrics). Clean out lint with every bobbin change. If you get thread tangles or impacted lint in the bobbin assembly and have to take the ring out of there, you will be soooooooooooooooo sorry! Even the most experienced techs have a hard time getting it back in correctly. I am a sewing machine technician and have torn my hair out over that. Other than that, it is a super machine!
Oh, test your machine for thread thickness. I have a Singer 201 hand crank and a Singer 201 with potted motor, and neither likes thread weight of thicker than 50 weight. 60 weight is good, 100 is good. Silk thread would be great. Polyester thread should be fine, but test.
Whatever you do, do not attempt bobbin work (thick threads in the bobbin) or free motion quilting with this machine for the reason given above.
Cricket