Professional graphic designer or user interface creator

I have a completed website which has a basic layout with one central focal point for each user to concentrate on when they are logged in. I'm not completely happy with the front end look, the layout, and user experience. I'm looking for someone who has experience with creating user interfaces for websites, to assist in coming up with a few alternative user interfaces and overall layouts in order to boost the overall attractiveness appeal and user experience of the site. I'm looking for something that looks slick clear and tidy yet stripped back such as with Twitter or Facebook. Please can you provide samples of your previous works in this area if you apply for consideration for this job. Ideas for the visual style: This is what I'm after, but in summary slick, stripped back and stylish Extra notes: I have a completed website which has a basic layout with one central focal point for each user to concentrate on. I'm not completely happy with the front end look the layout and user experience. I'm looking for someone who has experience with creating user interfaces for websites, to assist in suggesting alternative user interfaces and overall layouts in order to boost the overall attractiveness appeal and user experience of the site. Please can you provide samples of your previous works in this area if you apply for consideration for this job.