If I remember correctly, Dressmaker is a "badged" machine, which means that it is a machine made by a company to sell to several different retailers.
Post a photo of your machine. If you go to the area below where it says, "Go Advanced", you can post a photo from there. Someone may recognize the original maker from the photos.
Janey is really good at finding manuals. Victorian Sweatshop is a great resource (Janey posts there, too). They may even have a manual in their files when you figure out the manufacturer.
bkay