DreamHost support can't really help you with this, but it is not that difficult and you should be able to do it yourself with a little planning and preparation.
The WordPress Codex has an excellent article that describes step-by-step how to move a WordPress blog in most any situation, and you can find it at:
I think it does a better job of walking you through the process than I am likely to do here. You should read that material and give it a try! If you have a particular problem or question, post back here and I'm sure one of the wizards here can answer it for you.