Sterling Bathtub/Shower Valve

I've got a Sterling 3 handle bathtub/shower valve setup that needs to be rebuilt (diverter doesn't work; cold water shutoff is problematic). Probably 30+ years old (guess). Any ideas where to get replacement parts?

Thanks.

Call 1-800-STERLING first.If its 30 years old the parts could well be NLA.If so its time to start searching the web.Just surfing around,I have found at least a couple places that deal in obsolete stuff and ask you to send the item to them and they will see what they can do.There are also places that have extensive pictures and drawings of old faucets and parts that you can try to visually match with.
Google.com is your friend.