Artists Shop - Finish an on-line store. -- 2

I have a website that has multi-sites within the domain name of StudioOutback.com. For this bid request, I only want the e-commerce section finished. This site has the possibility of many sites but only the “Artist” sites will have e-commerce Shops. Currently the previous coder tried to use Magento as the shopping cart. You can delete Magento completely if you have a better shopping cart that will handle individual artist's shops and be able to use one payment gateway. The following is the way the previous coder designed it but can change at this point to go directly into the artist's personal shop (only that artist's products) and show all products thumbnail photos which link to each products page with full description, large photo, and all related fields associated with ordering. On any Artist" website, in the "Main Menu" there will be "Shop" and when you mouse-over "Shop", a sub-menu opens up. In the sub-menu will be different products - Music Downloads - Caps & Hats - Tee Shirts - Music CD - Videos - Posters & Photos - Specials. If you click on one of those, it will take you to a page with only those products (If you clicked on "Music Downloads", it would open a page where you would see a thumbnail of the album cover and in the description area it would explain that this download is a set of three songs in one download. The price would be $2.50 for the three songs. There would be a description area, then a "Price" frame, and then a "Add To Shopping Cart" button. Below that, you would see other downloads available exactly like the above except it would be 3 different songs. If you clicked on "Caps & Hats", it would open a page with only caps & hats for sale. Each row will have a thumbnail photo that goes big when you mouse-over and a Description, Size, Quantity, Price, Add to Cart) in rows as a list. I will need to add more Hats & Caps as they become available. I am open to changing the complete shopping cart but due to [login to view URL] being a multi-site site, some customization of the code might be required.