automatic login and query

Have: a website that uses emals shopping cart w/credit card gateway. Have: xls spreadsheets on our server which contain prices for products. Have: access to a third party website via un and pw, which contains the product availability (stock) info upon providing un/pw and product code in question. Have: complete product catalogs in pdf format on our server. Need: Software developed (scripts, sql, etc.) that can be embedded into our website that will locate the product in our catalog based on a part number search, display an image of the product, and provide price and availability of stock. The page displayed must also include the add to cart and checkout functions.