Jeep Cherokee 2002 with 3.7L engine petrol

Where can I buy OEM crankshaft and Camshaft sensor since here the dealer says the have discontinued making them 

Maybe you can find some on E-Bay. Rock Auto may have some new/old dealer stock, but buyer beware, the return process for rock Auto is harder than returning the One Ring to Mordor.
I've had limited success getting them from the junkyard, but there's a real good possibility that just about anything old enough to have been scrapped may have aftermarket sensors in it.
It's sad when our hands are tied from making a quality repair due to lack of quality parts.

Thanks! The owner bought aftermarket ones and the cannot start the vehicle but if i use the old ones it's starting