Just kunena forum width and enter if over18 or exit script

hello all, for this project I need to make this simple change to my site in joomla / virtuemart: 1) increasing the width of Kunena Forum 2) being an adult site, I need anyone coming on my site from any external link (google, facebook or other sites) see first thing this js with the option to choose whether to enter (if over 18) or exit and be routed to another site. to see what I mean just go [login to view URL] good luck!