Create the backend of my online site - repost

I have already developed most of the site and I have only been left with a small section(Back-end). This site is to be used to receive article writing orders online and then post it to the admin for writing. The site has a price calculator which calculates immediately when a user enter figures and then its transferred to the order form when the user proceed to put an order. Therefore i want someone who will create a back-end section, where the users will review their completed work posted to them ready for their approval and [login to view URL] the back-end the user can comment about the work and even post another work to be done.