Nice content.. I think you got a great job. Now do all the necessary things that they've already mentioned above. Directory submissions, article submission, forum posting and be sure that this is a quality and related backlink.
More content is not an issue here.. Its how you going to optimized the page for you to have the quality backlinks.. and one thing more, it is important for you to know that sites with high Page Rank doesn't necessary mean that the site itself is good.