I think i know exactly what you are looking for. For my websites I use a company called RankPay and they do performanced based SEO. Not only is it relatively cheap depending on your keywords, but YOU DON'T PAY UNTIL YOUR SITE IS RANKING!
I've got a bunch of sites ranking with them for extremely competitive keywords. It was pretty easy for me to choose them because there is literally no risk involved. You dont pay a dime until you start ranking.
If you're feeling confident or you are a quick learner, i strongly suggest SEOmoz. They have become a HUGE community for people learning SEO and they provide great SEO software and tools. You can create a campaign where you can track rankings, find problems to fix in addition to a huge list of resources.
With either one of those, you will be on your way to better rankings!
Heh. Put the right keywords in the 'keywords' and make sure they are relevant to the page's content. Then link to the site from a web site that the search engines regularly crawl. That about all SEO's do and is the best you can hope for.