Adroualt:
Are you referring to TA airport or the city of Tel-Aviv ?
From the airport you can take a regular taxi (about 250-300 NIS) or a shared taxi (62 NIS per person). Both will deliver you to your destination.
From Tel-Aviv (the city) you can take a bus : either the 405 from the Central Bus Station or the 480 from the Arlozorov Terminal in North Tel-Aviv. Both go to the Jerusalem CBS. There is also sherut service from the Tel-Aviv CBS to the center of Jerusalem; it does not take you to your destination. The bus costs 18 NIS and the sherut is approx. the same.