Website creation

I need a complete web design from scratch, the site is a trade only site for registered users. I need users to be able to add a product for sale on the site to be purchased by other users.
Credit card integration required with service provider.
Free demo account for non registered users.
Classified ads section for registered users.
Items placed for sale will need to be approved by administrator before being entered on a live screen showing items for sale.
Full details of product will be withheld until purchase made for security reasons.
Seller to approve purchaser prior to payment.
Automatic e-mailing systems to be included.
Text provided. Will need version in at least three languages. Translation provided.