It sounds like you are trying to buy it again. There should be no checkout area. Login to your account and go straight to your download area to get your extensions.
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.