Good choice. DreamHost provides a 'one-click install' of Wordpress v2.0.2 directly from the web panel.
Since you do not have access to the blog database, I don't see any easy way to migrate the posts. Even if you did have access to the database, migrating the posts could still be difficult if you were using different software on your previous host.
If I were you, I'd start the new blog with fresh outlook and new posts
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