Franck

Hi everyone, I just bought my first Subaru Impreza Outback Sport 2006 last month and the gas mileage is not what I'd expected. Subaru says the car should be doing 23/28 and I'm only getting 17 at best doing 50% in the city, 50% highway.Right now I only have 700 miles on the car and I was until last week using the cheapest gas. So my question is , Am I going to see a significant improvement once the car has been broken in ( as I was told by a couple people ), is this a common thing on a new car to do poor gas mileage for the first 2000 miles or so and finaly what can I do to improve this situation. Bythe way, I love the car. Thanks Franck