Add new function to my website (Wordpress)

Dear Freelancer community, I have bought a Fiverr like wordpress theme but I would like to add a option to make it slightly different. This is my current website: [login to view URL] (nothing has been done to the theme because I need help from a professional first). At this moment it's possible for people to add a service they would like to sell to others. The option I would like to add is that people can also post a project that needs to be done by someone else, so people can bid on the project. The project owner can select a winner and work with the bidder. Like this: [login to view URL] I'm looking for someone who can add the option to my Wordpress website.