PHP Programmer & Web designer Needed

I've got a social network web site based in php, but the quality of its code is really bad, it's not secure and it lacks a lot of features I'd like to offer to my users. Moreover, it's UI is not nice (bad design & bad graphics). It is a big application with many functionalities, and the deadline is tight. I need an experienced & high qualified php programmer, with knowledge of UI design and a huge portfolio based on programming good practices, in order to: i) fix (or completely rewrite) the code, allowing it to grow in a manteinable way. ii) make the application secure, bug-free. iii) completely redesign the UI (graphics included) & ajaxify it, making it attractive and modern, completely css based and w3c html strict compliant. iv) localize the application (UI in various languages) v) implement a mobile version. vi) propose and- if approved- implement changes and new features in the UI. These changes will be covered in a later phase 2, with its own budget. I will only consider candidacies with a huge portfolio of great quality UI & great performance 2.0 web sites based on php & css.