514760 MP3 Download Store Wordpress Script Customization

We are desperately in need of a new mp3 download store to replace our current aging platform. We've recently been testing the WP-ecommerce plugin for Wordpress ([login to view URL]) and we like the functionality a lot but it is lacking a couple of essential features that are needed for our store to operate. We need the following abilities to be custom coded in: -Ability to sell albums with individual tracks inside (IE someone can choose track 5 and 7 only) -Back end login landing page with sales states for each artist. (Can use current wordpress login system if that's easier) -Ability to upload new album mp3 source files via the backend Wordpress panel. (This partially works now) Please take a look at our current store [login to view URL] and see how the album and song layout looks. It needs to function in this same way. *** PLEASE NOTE *** No graphic design work or template layout work is needed. We will be taking care of that. This project is for functionality only. This is a very urgent project and we have the funds available right now. Thank you.