If you have gone 4 months and nothing, that does sound like maybe you either aren't doing something right or the products don't sell. What can you tell us about your traffic?
Nice website. I took a look and realize that the description pages of your products aren't very long. You should consider redoing them to make them more descriptive. Also, are you driving targeted visitors to the home page of your website or to the individual product pages? What are you currently doing now to drive traffic to your website?