If you uninstall, your database will magically appear in your panel's MySQL section. You will need the following information from that section of the DreamHost panel:
1) Database Hostname
2) Database Name
3) Database User
4) Database User Password (clicking on the User name will bring up their info, including their password)
Next, click on phpMyAdmin in the database listing and log in with that User and Password from above. Then click on the database in the left column to get a listing of tables in the database. They should all start with something like wp_xkadlkjsdf_. You will need this information for your new WP install.
Once your new Advanced Install is done (as a fresh start), you'll need to FTP in and edit the wp-config.php and update the configuration file with the information gathered from above. Once that's done, your new WordPress site should look like your old WordPress site.