Website Creating + vBulletin Marketplace creation

Basic Background: We are trying to make a website, but attached is a vBulletin Forum with a navigation bar that links to the marketplace that we need created. The marketplace will give users an opportunity to add a listing with a Title, Description, Custom layered category selection, multiple pictures, sizes, colors, etc. Aside from this, users can add offers on pre-existing listings by either selecting a previous listing of their own, or creating a new one. This offer that the user receives will go to a selection in the navigation bar titled "My Offers” and from there they can accept or decline. When the user sent an offer on an existing offer with a pre-existing item, that item will become unavailable in the market place. If it’s declined, it will be automatically placed back into the marketplace where the user can then accept offers, or use it to offer on another item. If the offer is accepted, a notification will be sent to their emails stating the item they will be receiving. When they click the link in the email, they will be sent to a page where a shipping calculator will price the cost of shipping from our warehouse to the opposing users. They will pay both shipping fees (shipping their package to us, plus the cost for shipping to the other user) + a $10 fee. All will be sent to our paypal. After they pay, they will be brought to a page where they can print out mandatory documents. They will include each users name/address and the item they are trading. When a transaction is complete, the user who got his listing offered on can click “Finalize” and from there they can leave feedback for one another. If there is an issue, either user can click “Report Issue” and send an email through our website to a specialized support email. Before continuing the trade, each user must print out 3 pages that they will be redirected to after paying: 1- A set list of instructions 2- A page with their address & our address (a shipping label) that they will tape to the box (If the item comes with a box, ie. Shoebox, it will have to be placed inside a brown or white (depends if they use UPS or the Post office) shipping box. 3- The address of the opposing user (They will place this in the box with their item) If the transaction goes smooth, the transaction will be archived by a serial number, ie: “ss-1” would be the first transaction to occur on our website, and so forth. This will be archived for admins into a special forum (which will not be seen by anybody but those with special permissions), and for the two users who swapped (this will be in the “My Offers” section, but then into another section called “Completed Transactions”). As of now, we have a basic layout & the shipping calculator. Nothing else has been completed, This will all be done through vBulletin modification. We have: -Domain -Website Layout (Just the graphic - no coding) -vBulletin -vBulletin theme (which we'd like modified for the above) -Shipping Calculator