This machine has been discontinued for several years and as you've discovered, it doesn't have a USB facility but used Brother embroidery cards which were available to buy and held several designs on each. There are a few on e**y at present, one of which has a good set of photos showing the separate embroidery attachment and a description that details the machines abilities, including its 7"*5" max hoop size.
E**y may also be a useful source of Brother embroidery design cards. Sorry that I can't be more helpful.