PHP script customization - CodeIgniter

I need to customize a script written using CodeIgniter. The following customization is the one right now needed. A few more will be done and will be awarded to the right freelancer. 1) Current script needs a page where templates can be uploaded 2) Another page which faces a vendor, which allows the choice of template along with banner, title and a few details including their PayPal information 3) The vendors landing page will then need to be rendered using the template chosen 4) When a buyer decides to buy using PayPal, the PayPal API is called and the chosen item is added to a cart for later check out. A sample site with be shown to the right freelancer. Only freelancers with good experience in the tagged skills should bid