Just copy and paste the form and set the form action to submit to the original page... You don't need to move any php code if the form submits to the page with the php code.
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.