Capacity Planning View/Reporting

Client is coming from At Task and is looking for an alternative tool; however, client requires capacity planning features/reports in order to answer questions such as the following:
"My PS team should deliver 500 hours over the next quarter and we are currently planning for 350 hours of work. Do I need to hire more resources if we take we were to take on X amount of hours of work over the next two months? If so, how many for FTEs?"

Eyeballing the percentages within the current resource load doesn't provide an FTE count.
Client's current system, AtTask, has the following report available, http://screencast.com/t/pMX5AguP3gt, which includes:
- "Available Resources", as seen in the image. It's where you specify how many resources you have available in the next X months/ quarters, typically by using FTE.
- "New Remaining Resources" - the "Available Resources" minus the planned resource load. This is a breakdown of how many resources I'll need to hire/fire by resource type.