cost for a new or rebuilt 3.5 engine?

Hey guys. I've just found this site and found alot of kool ideas from from here to do to my car. UNfortuantly i put my 1997 3.5 intrepid into the shop for the oil light keeps coming on...but it still hass plenty off oil in it. Now the mechanic says there might be rod nocking and i should might start looking for another car. And he would only say that it would be very expensive to fix nothing more. So i was wondering how much would it be for a new or rebuilt engine. I really don't want to lose the intrepid. Thanx and help would be greatly appreciated!