Hello hazey7,
I ahve now owned mine for a couple of months. The MPG has got better the longer I've owned it as I was a little heavy with my right foot when I first got behind the wheel.
If you push the car mainly doing town driving you should average between 24-28MPG. This generally works out to around 380-420miles to a tank.
More recently, with motorway driving keeping between 70/80 (occassionally a little quicker) I have average between 42-46MPG and managed to get around 570miles from the tank.
Hope that helps a little?