Depends on the kind of life style you want...
In good neighborhoods (Palermo, Belgrano, Recoleta)
Rent one bedroom aparment: 7000
Expences: 700-1500
Dinner: 180-300 per person
Drink at bar: 100
Coffe: 50
Internet and cable: 1200
Subway: 7,50
Buss: 6,50
Theatre: 200-500
Cinema: 150?
Car expenses are quite a lot. So... i would suggest, dont even bother...
You are gonna be able to live... ok...