Adult site seo

I require the services of a professional and experienced SEO to gain high search engine positions, in the TOP 20 on yahoo and google for 2 competitive keywords. The theme of the site is adult dating. Please note that no payments will be made in advance. Payments will be made on a monthly basis, over a year time, based on continued performance of the site. The success of this project may lead to further similar projects. Serious and experienced SEO experts are required for this and people without the necessary skills need not apply.