Calculate budgets in $ using a charge out rate

Our projects are developed by a partner.

Each contractor working for that partner has a charge out rate when doing a particular activity (Deployment, Design, Development, Documentation, Requirements, Testing). We use the native TFS "Activity" field for this.

We have a number of Bands that a team member may be in: Senior, Mid-Level, Junior, Intern.

We have a matrix of charge out rates; each contractor is related to a Band, and the charge out rate is determined by the Activity.

We would like to be able to calculate the total budget used for far in $.

For example,

John -> Senior 
Requirements 10h @ 50 = $500 
Development 5h @ 40 = $200 
Total = $700

David => Mid-level 
Development 30h @ 30 = $900 
Documentation 10h @ 20 = $200 
Total = $1100

Claire => Junior 
Testing => 20h @ 20 = $400 
Total: $400

Total Budget Used for far = $2200.

At a minimum, we need to be able to export the 'Activity' field of the tasks as part of a budget export and do the calculations in Excel.

It would be excellent to have this information available in real-time so we would know the current financial status without having to do exports and calculations. These calculations are currently very time consuming for us and having the information available whenever we need it it would be very valuable.