Hi Pat,
Most of my experience with this is in MS SQL 2000 but it should be almost the same.
Its not that simple. To add new articles to your publication you will have to quiesce the database, or wait until a quiet time. Manually populate the new subscriber tables with your new articles (SSIS pkg or scripts), then drop the subscription, add the articles to the publication, and re-create the subscription. You may also need to refresh the replication stored procedures afterwards.
Chris.