Congrats! Your new baby will take any low shank foot, old or new. Easily found on ebay and at antique or thrift stores. If you are looking for an original case, I am not sure where to look. Just beware that lots of the original cases have horrible musty odors. My case was so smelly that I opted for a padded case made for the FW's. I purchased the padded case from
http://www.featherweight221.com and have been very pleased with it.
You are going to love your new FW!