Greetings,
It's good to hear from a fellow xA owner -- I have a 2005 RS 2.0. I have averaged just over 37mpg for the three+ years I've owned it, including winter driving. My high (so far) is 43.5mpg -- though now that I have duct taped the upper grill opening (the RS 2.0 has a unique open honeycomb grill), the current tankful is on track to beat that!
Is yours a 5-speed or the automatic? the reason I ask is, on my car the engine revs to ~2,800RPM at 55mph and ~3,400RPM at 65mph. I know people who own a 5-speed Yaris sedan (virtually the same platform) and they do ~2,500 at 65mph...