You probably shouldn't have rushed ahead and submitted your site to the Open Directory so quickly. Too late now though I guess. I do search engine optimization as one of the major components of my job and even the seemingly simple process of submitting your site to a directory is a fine art if you want to get the most bang of it.
Read up on those links previously posted (searchenginewatch.com and searchengineforums.com) although I must warn you that there's a lot of overview info and even then it's not as easy as it first sounds. Most people just assume you slap a few meta tags on your site and submit your site and you'll be fine. That hardly ever works any more. There's SO many sites out there these days it's becoming increasingly harder for sites to be found via traditional search engine optimization. And with Google's heavy dependence upon link popularity (a factor many search engines are increasingly giving weight to in their ranking algorithms), it's harder for smaller sites to be found as they don't have the link networks established that biggers sites have. A quick glance at your site shows it has a decent amount of links pointing at it though for something on this level. The best advice for a quick fix would be to rework your title tags and beef up your content to have some depth of content that will seem attractive to search engine spiders. And if you can afford it, you might also want to look at submitting your site to Yahoo's directory (make sure you use those reference sources above though to make sure you do it right.) Yahoo is still the king in generating search traffic.
You might also want to look at pay-per-click services like Overture and Google AdWords. These services have phenomenal reach and if setup and managed effectively can offer amazing traffic potential. They offer phenomenal click rates in comparison to anything other than a top 10 ranking in a search engine.