Web Design - Shopping Cart System

I currently host and maintain a website and am looking to start another. This new website should be built using Joomla with a simple, clean interface aimed at providing a shopping cart system to sell downloadable music and audio samples. The aim of the site is to showcase music, audio, sound effects created by my company for use by film, television and media artists that require this type of media. I am looking mainly for the shopping cart component to be designed that would allow the following: - Integrate with Paypal payment system (my business account is already setup) - Present browsable files in a simple catagory/table format with the ability to display an image, description, insert code for a preview player to play a low quality preview of the file (hosted on a 3rd party site) and the "add to cart" button - Once the user selects their files they then complete payment and once accepted, the user would receive an email with the links to the files (which would be WAV files zipped and also stored on a 3rd party hosting site). - Download links MUST be secure so there is no way to discover the true source of the file - Links should be able to expire in a preset time - I will complete design and filling in content of the site I just need the working model for the shopping cart and a simple template as a starter. What I have in mind is something similar to this site: [login to view URL] The way you can browse collections and samples easily, create your shopping cart and have the files immediately after payment. Much appreciated if someone can assist.