Update frustration

I updated one of my websites to a new version of a program that it had on it and the program immediately told me that it could not run the site program because it has to have PHP 5.3.2 and I have PHP 5.2.17 installed on that site. I cannot change the PHP version and am not sure just how to go about contacting someone that can change it for me so... my site is apparently down until I can sort out what is going on and how to get my PHP version updated. So frustrating that I just had to vent about it before I scream.