Mp3 Shopping Cart with Admin and Paypal Support

I need a Shopping Cart to sell mp3's. I need to be able to receive payments using Paypal. The shopping cart must have Administration where i can add more mp3's later, see customers, sales reports, downloaded files history, and the most important feature be able to deliver a protected url to customers for downloading the mp3's. On the Categories/ Products, I need to be able to create categories as needed as well as create new products. Products, I need to have particulary 2 options, besides the regular shopping cart stuff, I want to be able to setup a SAMPLE FILE which will be in SWF format, and a MASTER FILE, which will be in MP3 format. Store front, I want it to be easy and understandable something like zencart yet not the same. I will help during the entire process indicating you what colors i want, I work with CSS so If you make a CSS file for the application, you can send it to me and I can customize the look of the site. Thank you, and I hope to do business with you from now on!