Depends what you understand with "dating" really. There's a difference between having dated a girlfriend than actually having one. Can you tell me if you have any hearts on the radar and map located in the north of San Fierro and in El Quebrados - the desert?
Besides, do you have any mods installed? Where have you got the game from? Could you link me to the save file you downloaded? Do you happen to be placed after getting bused / dying somewhere else than in front of the police station / hospital?