Categorizing And Sorting Data

Every week I export a payroll report from my payroll provider (sample attached). The report is sorted by employee name. I need this report to be categorized by department and show a subtotal for each department. The payroll provider does not provide a means to put departments in the system.

I'd like to find a way to automate this as much as possible. The final report has to have a column that reflects each employee's department and the report must be sorted by dept with a subtotal for each dept. I tried to do this using a second worksheet that lists each employee and the dept they work in and linking it to the payroll summary using =IF; that obviously did not work.

Does anyone have any suggestions as to how this can be accomplished? The process would need to be repeated for many clients each week, so I'd like to keep it as simple as possible.