You have your form action set to post directly to the RequestforQuote.php page. You need to submit to the current page and redirect to the RequestforQuote.php page after it adds to the cart.
Change your form action to: action=""
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.