UI stands for user interface, the more visual aspect of a website, which may include pictures, but that is not really of necessity. Have a look at the following link (
http://webstyleguide.com/interface/user-centered.html) - I am not really sure what your site is offering, it seems like it is a forum for person X to link up with person Y to work on tasks or something like that. If that is the case then there are far more user friendly and graphically inviting sites out there that you are competing with. If this site is IT related then there are sites such as scriptlance and odesk. But the key factor for your is get a web designer and get rude of the 1990s look and feel.