Create forum for website

My website is [login to view URL] I want to create a forum for my website that is very similar to this: [login to view URL] I want it to blend perfectly with the already existing graphical design of my site. I also want it to be VERY clean in terms of coding It's ok to use a template or already existing template software BUT! It is VERY IMPORTANT that users who log in to my already existing log in interface ([login to view URL]) can have access to the forum. I want to have good moderation and some form of spam protection. ## Deliverables full backup is required before modifying ANYTHING on my site