How much a week or month would i have to make to afford this?

Me and my girlfriend wants to get a 2009 Scion Tc after all taxes and wat not its $18,641. We got new jobs working at the same place making 400+ dollars a week. We still live at home and we both have credit cards that were never late on. our previous job we held over 2years. Is this enough money to afford this car were going to put 3000 down. if not how much do we need to be making a month or week? O yea were only 18 and im tired of driving my beat up car that iv had for over a year and never got one ticket or into an accident