Try Computer.Software.Application Suites.Application Suite.Name = "Microsoft Office Professional 2007"
You may need multiple lines for the different flavors of Office 2007 you may be using in your environment.
I you have LDMS, you have a module of Software Licensing Monitor (SLM)
That indicate you, how many use a product, how much time and more than.. Check on SLM
You can make a report of course.