Build Online Store

I have Yahoo Web hosting Starter and a domain name. I need to build an online store selling cameras, computers, and so on. I will need some help to build the store. Among other feathers, the store must (1) be categorized in the left navigation section, and have search and sort functions to allow visitors to find the products quickly, (2) allow me to update over 10,000 product with their prices, descriptions ( with pictures) and other info in a very efficient way. I would like to be able to upload a excel spread sheet with the products info. The spreadsheet will have columns such as manufacturer, product name, item number, and price. As far as the picture is concerned, I do not how I can link them to the related products in an efficient way. So…please provide a solution. (3) Calculate the shipping cost via UPS, FedEx, or USPS. (4) Calculate the Florida sales tax. (5) Allow me to provide discount by giving customers coupon code. (6) Allow me to put products on sale in big flashing pictures on the first page. (7) Allow me to administrate and maintain the website independently after your coding is done. (8) Customers to pay by credit card and papal. I will use the shopping cart at openecho.com. I do not want to pay extra money in the future to update the price list, change the pictures…After the coding is done, you will need to configure the website to ensure it is working. Besides tech aspect, I will also need help in graphic design to attract visitors.