Angela-
Your story book cards are very cool, and unique. If you have "own" blog, with "blogger" or one of the others, put a widget on that. I really don't think the widget links from Facebook and Myspace link to many sales. (Anyone else have sales from these links/widgets?)
Or if you have your own web page, put a widget there. Create a "buzz" for your particular type of card . . . Link up with other "like" blogs or sites. Think of maybe creating a "Squidoo" lens about your style of card.
The more your name, store name and keywords on cards appear in search engines (Google, Yahoo, MSN) the more exposure you'll get and the more likely-hood to get a shopper to any of your cards. It seems that most shoppers find cards by a net search. Focus on the "specialty" cards you have and it will help to bring folks in to see other cards you have.
Just some suggestions!
Ernestine