Extending RBS script from cogzidel

Hello, i am looking for an experienced CodeIgniter/PHP developer who should work on a portal based on the free RBS script from cogzidel. You can take a look at the script on their website. What i need is built in shopping cart for designers/coders. This is the workflow: 1) Designers and Coders can upload digital products into the shop. 2) Each product can have up to 5 screenshots. 3) When a product is being uploaded the designer/coder need to fill in: name, description, category, price, filetypes (like: eps, php, fla etc.) 4) The user can buy the products through internal payment system. He needs to deposit money first and than he can buy the products. 5) After payment has been done the user can download the products from his download tab in the 'My Account' section. The downloads are always available after buy. 6) Downloads must be secure and should not be downloadable from not logged in users or from outside. 7) The product will get a new site called 'Products' that will look the same as the starting page, where the latest products are shown. 8) The searchoption on the homepage should be extended with a new tab for products. 9) For each product in detailview a comment function should be implemented, where users can ask the designer/coder about product problem or bugs - like in [login to view URL] 10) In the designer/coder profile a new section should be visible where the latest products of this user are shown 11) A small shopping cart should be built in somehow That are the main steps for shopping cart. Beside that a few bugs should be removed. Please apply only if you really have experience with CI framwork. Thanks, Chris