Build an Online Store with Affiliate tracking

We have an existing eCommerce store ([login to view URL]) that we wish replicated, and expanded. Currently it is using leaddyno for backend tracking which is integrated with both Paypal, and our credit card processor. We'd like this replicated, and added to a new domain, with new branding, and the added ability to add products to the site. No source code is available. We're open to new solutions if you're aware of a self hosted php system that can achieve our goals, without monthly charges. This is a subscription based service that is being offered, so expandability (as mentioned above - adding new products) is important to our future goals.