I would suggest a cold air intake and alloy wheels. The intake will bring your average to around 40mpg and give you much better acceleration. The wheels just look good and reduce the overall weight of the vehicle and will impact mileage some.

 

I get 26mpg
I brought the car to the dealer five Times and they say nothing is wrong with the motor

 

Mines doing the same thing. Bought it new. I used to break 40. Now barely break 30. Mostly hit 28. No one will even look at it. I'm frustrated. I don't think you have a lemon, I think it's a shifting problem. It's a 6 speed, and that's where it gets its mileage, not the small engine. Seems lots of people are having this problem.