178058 wordpress post rotator

I need a php script creating to run as a cron job to do the following. 1. Find the oldest post and update the post date to the current date and time. 2. The script should have sql that i can edit that is capable of excluding from the update posts by number and exclude posts that are in one or more of a list of category numbers 3. It should not do any update if the newest post on the site is less than 12 hours old. The job will probably be run every 2 or 3 days. Nice and an easy job for someone who know wordpress php and mysql. I just need the script, no install.