xls to web data retrieval

This project is somewhat complex in nature. Currently using Miva Merchant shopping cart, [login to view URL] I need to export daily the product file (around 2,000 products) to a flat file, csv, dat, etc and edit it with the appropriate headers in excel. Then upload back to the site this file for data to be called into a form/html file. Miva currently has an export utility to perform this task. The main reason is for our customers to be able to load this file into their browser to see what items are out of stock, closeouts, or just simply a summary of product reference, etc.. To further explain, we are a drop shipping company, and our customer is the dealer either selling our products on their own web site, or on online auctions such as ebay. If an item goes out of stock then we are currently making it inactive until it is restocked. If the item is inactive on the site they cannot search for the product through the normal shopping cart, however they can look at this area of our site and reference the product from our entire product database file. I would like to have this data neatly arranged and manageble, as the csv or data file will change daily. After this shell is built, there are many additional expansions I will need to develop also retrieving data from this same file. Any ideas or questions are welcome.