Updating software can be a pain. But not always. It might not be as difficult as it might first appear. If by looking at your code, the includes, and the style sheets you are able to determine what software the developer used, then patching it can be relatively simple. Most software packages have details on how to patch their programs on their support pages. Sometimes it's automated, sometimes it's a matter of selecting a file, finding a section of code, then adding more code before or after that piece of code. Or else replacing that code with another piece of code.
Good luck! :)