eCommerce store required with CMS backend

We currently sell on Ebay and Amazon and now want to set up our own ecommerce website our requirements are : - professional looking front end - simple user interface - clean design - multiple product listings (500-1000) - product drop down choice ( eg size, colour) -must easily be able to add attributes and values to each product - back end stock management and reporting - shopping cart + payment integration - registration and login - bulk product upload by CSV / excel - Search facility for products and ability to sort results by price high / low etx we are looking to start this now for launch within 30-60 days we are not tied to any particular framework, just looking for a shop that works. we would be happy with an off-the-shelf solution providing the end result is professional. Please note design and CSS will be done, so it will be just the programming Need a reliable and fast worker with good examples of eCommerce stores to see.