I don't do Etsy, but I am just starting to get some of my stuff out there to sell, too. As someone else pointed out, I think cards are usually more of a "on a whim" purchase, usually in conjunction with something else. I tried to sell some on ebay with no luck, but I have some cards and collages in a shop in Santa Monica, and have sold a few cards through there. Also, a lot of what I do is also textural like your embroidery, and I have found that people like to be able to actually touch it. Maybe getting some out in a shop of some kind and making sure your Etsy address is on the back of the cards will be helpful because they will be able to see and feel your cards, and once familiar with what you have order from your site if they want more.
By the way, I think your prices are very reasonable, and pretty on target with other handmade cards out there.