Do you want to ADD or REPLACE the DB of your freshly installed WP ?
If that is a replacement of a blank database, then this is a piece of cake. Use phpmyadmin to connect to your old database, click the "export tab", click to select all tables, and click export, using default parameters (just tick "gzip" as additional option).
Download the file.
Download it again with another name and compare if it has exactly the same size (I already had incomplete downloads, better make sure)
Then use phpmyadmin to connect to the database of the new WP blog, click "import", chose the download file for the old database, and there you are, you have it. You'll just need to run the (www.yourdomain.com)/wp-admin/upgrade.php webpage, a final click, and there you are, you're done :)