As jazzc noted, you could use SimpleXML or any of the other XML parsing libraries available on php.net.
Personally I like to use the Simple HTML DOM parser (which is available on sourceforge) to traverse the DOM/XML trees and spit out data. The class is tiny and useful.
What you will need to do (assuming you need to access the data within the curr_custs_aff block) is navigate to <root>, then <curr_custs_aff>, and finally <areas>. Once you are there you're going to have to select the children of <areas> and make sure they're after the area_name that you want to pull data from. It would be much easier if the XML was, well, valid I guess. It's kind of all over the place to be honest. This is honestly one of the main reasons I wish everyone would switch to a json standard =[.
Hope I helped!