its a 2.5 5 cylinder Turbo, so it aint gonna be great. Mine does 23 mpg and maybe stretches to 25-26 if i do a few long runs. I have heard people getting as low as 18's and 19's but have never seen that on mine.

If you have just got it, try and pull the KAM fuse for 10 mins which wil clear out all the fueling info stored on the ECU, then it will start a fresh, learning your driving style. This may help a little.

Other stuff like air filters, tyres, wheel alignment and tyre pressures will all effect an already poor average mpg figures.