Calculate Total Query Response Time...need help...

Ok,this should be fairly simple, but I'm missing something.
Most of this could be derived out of the DMV sys.dm_os_wait_stats.
CPUTime + ResourceWaitTime + SignalWaitTime= Total Query Response Time
Where do I get the total CPUTime? This is running time, so how to join historical and running data? There must be another DMV Can I get script for this? THx

Thanks, but I realized I would probably want to get all this info from current info, and not historical?
dm_exec_requests and dm_waiting_tasks seem like some candidates.
OK, I did this - but result doesn't seem what I'm looking for: Query response time in this case is 3+ hours???---------------------------------
Select @@cpu_busy as CPUTime,signalWaitTimeMs=sum(signal_wait_time_ms)
,resourceWaitTimeMs=sum(wait_time_ms - signal_wait_time_ms), @@cpu_busy + sum(wait_time_ms - signal_wait_time_ms) + sum(signal_wait_time_ms) as TotalQueryResponseTime
from sys.dm_os_wait_stats------------------------------------