Custom CMS (existing) and Ecommerce front end

It is a very large project. We basically use a custom open source ERP system called Weberp comprised of a PHP front end and a mysql backend. What we want to do is create a website (ecommerce) that uses the same database as weberp so we can use the ERP system as a CMS and accounting page for our transactional pages. Email for further detail. - Expected timeframe would be 4 weeks constant work. - No Part timers please - Extensive mysql and php knowledge required - Ability to work with a pre-existing database - Perfect english required - Experience a must (with a portfolio to back it up) No open source ecommerce solutions! Fully customized front end is required!