Yes, you can purchase a domain from any domain provider, including Dreamhost. Do that and then let me know and I'll help you to finish configuring it for use.
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.