Website eBay Checkout integration

We need a ebay checkout feature on our website. In other words if someone buys a item off ebay we want them to be able to checkout out via our website. After purcahing the item the customer should be able to click a link on the auction page, or automated email (that we send them). The link should send them to a page on our website there they can enter their unique auction information and through the ebay API bring up all the details to for their auction. They should then be asked whether they want to pay via credit card or paypal. What this project is asking for is a php page that can request the ebay information once the ebay user name and auction number (that are entered on our website) for the winning item. We would need a list of the resulting url parameters that are returned and we can do the checkout pages via our credit card gateway or paypal. The second thing we would need is a php script that we can insert somewhere after a successful payment is made that will change the payment status for the corresponding purchase on ebay to “payment received” and the type of payment. For someone who knows the ebay API this should not be hard at all. Thanks.