Great concept and great start. Looking through your site, it seems theres a basic color scheme, and it's t-tone. I love SIMPLICITY (why can't google, Astrid and Catch stay simple???), which your site is, but at the same time, it looks very basic.
You have a lot of competitors out there, what do they do that is successful? Colors? Images? Mostly images and hardly any text? I would start by adding some sort of color banner or colorful logo on the top, this will really set the stage for your customers. This is tricky, because selling and buying websites can be a thousand dollor + game, so you need to stay looking professional.