Joomla website session tweak help.

Hello, I have a small problem with my joomla website. This is the link. [login to view URL] There is a form on this page which is processed backend. The data from the form fields is stored in the joomla session in the form of an array. I want to know that which file(backend) is processing this form and any possible way of overriding the array values in the session. Further details will be discussed on chat. This is a very minor tweak and budget is $10.. Don't bid more than that, it'll go to waste.