Affiliate

I am looking for a PHP developer who understands sessions. I am attempting to track users’ to this website: http://www.onlinemarketingshow.co.uk. I need to know what web banner they clicked through and whether or not they went on to register. A banner on an external site will have a link url such as [login to view URL] – this will link to the registration page and set a hidden form of id AffiliateCode to a value of 10293. The registration page page state must be maintained so if the user browses any other part of the site and then returns to the registration page, the form will still have the hidden form of id AffiliateCode and value 10293. When the form is sent we receive the code that tells us what banner was clicked through. The registration form is on an external secure server here; [login to view URL] I must have ownership of all code. I need to have this completed within 2 weeks of awarding the project.