well it depends upon driving condition and maintenance
how fast do you drive, faster you go the more it will take up
how is the maintenance for the vehicle, have you cleaned fuel injectors, replaced fuel filter and things like that....
If yes then probably your looking around 22 MPG if not then expect 18 or below.....
if you can do math, you can just figure it out by yourself....
http://www.ehow.com/how_2189992_calc...s-mileage.html