It amazes me how many people don't realise SEO is a huge job and should always be looked at as a ROI. If you want someone good then you're going to have to pay, simple as that. No-one worth their salt is going to take a job on those terms. Seo isn't cheap for a reason it returns phenomenal results when done right. If your making $7k a month revenue then start investing some of that profit. What says you won't cut and run when the site is ranking.