Sourcing TV Ads

Has anyone come across any software or some kind of algorithm that can be 
used to source calls to a TV station based on incoming phone #, customer 
phone#  and/or zip code; any other way known to man?

I have a system where I have access to incoming phone #, the customers 
phone# and zip code, also the operators can ask the customer the station 
they are seeing the ad on.  But the rub is the marketing folks say that 
asking the customer is not accurate, so I'm looking for another way of 
coming up with that info.  The marketing folks can provide a table of 
stations, zip codes and incoming phone #'s assigned to them, but how does 
one figure out based on zip code or customer's phone # which viewing area 
they are in?  Other than hard code or table every zip or phone exchange?

Any ideas are welcome! (even a long walk off a short pier!)

Thanks,

-- Jim Lowary
ToastMaster/Salton