Create a crawler

I have a database in MySQL. I need a PHP script that crawls this website [login to view URL] (which is a craislist-type website) and fill my database with all the posts from revolico.com. I will provide the list of categories and the .sql file of the database. The script has to be called every day, so the same post cannot be inserted twice in my database. Eventually I will start crawling other similar websites as well, so if one person posted the same in two websites, I do not want to have it repeated in my database. This means the way to avoid duplicates cannot be the time inserted, the script has to detect if the post (or a very similar one) is already on the database. Also, if the job is finished on time and running good I will re-hire the freelancer to do the other crawlers. This one is the simplest one and should not take longer than few days. Also, if you want to use another language we can discus it, as soon as it runs in a Linux box environment. Understating Spanish is a great plus, since the website to crawl is in Spanish.