86278 Advertising, Promoting & SEO

I have a relatively new website, [login to view URL], that allows people to trade items & services (and buy & sell). I need to drive more traffic to the site. I had began an SEO campaign and it has now stopped. I've done about half of my site's meta info & optimized content. I need to raise my search engine results (obviously). I currently have a few terms in which I come up, but not very many, and not very high. I would like the site to be in the top 10 when people search for various items or services listed by users, for example, "used law school textbooks." What I also want is for each new ad placed by my users to be found in search engine results. I'm assuming I would need some link campaigns, as well as some SEO (including a little more meta info). I would also like some press release/article submissions, & information posted about the site on as many websites and message boards as possible. I already used google & overture. I am open to other suggestions. You must have EXPERIENCE and be able to actually drive traffic to my site/increase search engine rankings. I am on a limited budget right now! There is also the chance that I would maintain you for regular advertising service, if all works well.