Design the PC and mobile UI for a facebook app

I am looking for someone to help design the layout for a facebook app I want to make. I need a design for both mobile and PC browsers. The app is a photo collage maker where people can very quickly and easily make a collage from their facebook photos. They should be able to select different default designs for the collage as well as swap out photos from their collect in to the collage. Right now I am looking for someone to just help design the layout, but it would be a plus if you could also do the full polished design after the basic layout has been approved. I need a artist that is fully up to date in their design skills and someone that knows all of the latest web design styles and how to use them. I am not just looking for someone to do a OK job, I need a real professional that does this for a living. Many more details and examples of what I want once I find someone. I am also a full time artist, so I know what looks good to me and I am very easy to work with.