Add custom fields to the Support System support ticket form?

I have a multisite setup with seperate sites for:

Membership

MarketPress

CoursePress

1 – I would like to add a way to designate the originating site with a drop-down list or from the originating link location.

2 – I would like to add categories with Sub-categories for their selections.

My goal is end user support rather than sub-site admins. End users of the store will have much different questions than those trying to take a course.