tyre pressures 17

I need to pick the forums brains i have just put on the car a staggard set of amg 17" wheels on a c class 180 2008 new shape there were standard 16" 7j wheels on the car http://i874.photobucket.com/albums/ab301/jontydt52/P1000645.jpg?t=1277553742 the tyres are fronts 225/45/r17 7.5 wide backs...