I guess with you being so new to php I would recommend some research into free CMS’s (Content Management Systems). It will take some doing, but you should be able to find something that will work with the site.
Another thing, find out which host they are using, find out what they offer with their hosting. They may already have something to help with this. If not find out if they support php, asp, or any kind of server-side languages.
If so then find out if there is a database that is avaliable with the hosting package they have.
This will be a good start. Find out this information and if you need more help. That is why we are here.