mysql/php mod to search spider

I use an open source search engine for my website. The site crawls my intranet when I give it url to index. it has options to index sites that have not been indexed or to re-index all sites only. I want to add a function that will allow me to reindex the sites by date, and this may or may not include sites that have not been indexed yet. The mod must include a link to this function on the admin page (your will understand that after you look at the source) pretty simple, I would do it mysel…