Buy and Sell online portal

I would like to build a website that allows the user to buy or sell items similar to eBay for example but less detailed. As administrator I should be able to manage the website content through a CMS. Visitors can search the website and buy items without necessary signing up for a user unlike sellers who are required to sign up for an account. Payment integration should be done through 2CO (we will provide the required parameters for integration). As for seller payment it will be done only through Bank transfer or direct checks so this is not part of the website. Notifications: ------------------ 1. When an item is sold through the website i would like to send an email notification for Admin and the seller stating that "The item has been sold for X USD. Seller will be paid after N days" where N is a configurable parameter by administrator. 2. When a visitor or a user comments on a specific item an email should be sent to Admin and seller. Visitor --------- I would like to allow the visitor to search by category or by free text form. The text form should be an auto complete text box that displays the top 10 matches. I would like to be able as administrator to promote any item as a featured item for a given category. Logo and design will be also part of this project. So whoever takes it he needs to handle it from A to Z. Finally, I m short on time and I really need to get it done very quickly.