Creating Budgets From Already Exisiting Entries?

Hi all,

I'm working on a database for my school that is designed to keep a record of each staff members activities that they go through during the year. With the activity information, all their expenses for that activity are listed (see database for more information). Anyway, for anyone who has the time to look at it, here is what I am having trouble putting together:

I have done everything except create budgets. I would like to be able to set a yearly budget for each department (Maths, Science etc.), with the ability to create a mini school budget (Junior School, Senior School etc.) from the sub department budgets. Laid out like this:

Budgets:
- Junior School
- Middle School
- Senior School $8050 (worked out from the total of the department budgets below)
-- Maths $2000
-- Science $3000
-- English $3050

What I would like to be able to do is get the Total Expense for each activity that each staff member has undertaken, and subtract that from that staff members working department (shown in database). I would then like to be able to create a report, showing:

Departments Budget
How much the department has spent
How much they have left in their budget

You can then use the figures for each department to get these values for an overall Senior School budget:

Mini Schools Budget
How much the Mini School has spent
How much they have left in their budget

Does anyone have any ideas as to how I could tackle this?

The database is available for download here:

http://seconddimension.com.au/Database/StaffProLearning.zip

(Hold down Shift when opening the database to access design mode)

I'll look forward to hearing from people soon.

sugar05