Update / Modify PHP Code

I downloaded a free and open source program for Customer Support from here: [login to view URL] This Program is designed for customers to be able to create a ticket and file a report on any issue they have, and be able to check and follow up on this. This program works like this: Customer has to enter: Name, Email address, Category, Priority, Subject, Message. After entering the above info and submitting the ticket, program sends an email to the customer and to our tech support with a link to the ticket just created. What I want to add to this program is that only customers with a User Name and Password should be able to create a ticket and log into the system. So I want to add is: 1) Option for user to create account with User Name, Password, Name, Store Name, Contact Phone Number. 2) User should have to enter User Name and Password in order to create a support ticket. 3) When user logs on, should have the option to view all tickets he created (filter by: All, Open, Closed) or Create New Ticket. 4) A Log when user logged on/logged off. 5) Each ticket should have a field "Billable" (true/false) and "Billed" (true/false), these option should only be viewable and editable by tech user only (not for customer) these fields will be used for billing purpose in the office only.