ecommerce/ order fulfilment site

I need to have a ecommerce site created, this is not your regular ecommerce site in the sense that most of the orders will be from external site. So we will offer products to sell on the site as well as allow customers to choose from other external sites we have listed to place order and we simply help them complete the order for a small fee and ship to them. Most of the customers are in africa. So the flow of the site will be a customer registers, login to there account and go through the different categories if they see a item we have in stock they order or they can click on the links or banners of other external sites that we will partner with and complete a order form that will show the item they want to order. The checkout process will need to have the option to add the shipping as well as the commission that we will charge. I have several example sites that I can show to give a better idea of what needs to be done. I already have the domain and hosting.