add feature to simple php script - PHP ,mysql

hi i have this script: [login to view URL] that gets articles from this feed: [login to view URL] and then every time i visit script ([login to view URL]) it show me random article. what i want is to modiffy in this script: so each time it shows random article from feed, it will put that link on myslq db so then next time i visit script it will show me random but not to reshow links already showed, so if all links from feed has been shown ONCE it will start showing again same links (for second time) after all links has been shown 2 times ,then ,if new link is added in feed then it will show new links 2 times and then start all links again for 3rd time. and will continue in this way