Congrats on the purchase!!! Hope you can join us on one of our runs soon.
I'd say it sound pretty heavy on fuel, but the motor only has so little km's on it, and the moving parts are going to be tight fit for a while.
When my parents bought thier ED XR6 wagon (new), I remember numbers like about 16mpg for the first while. Most of this was around town as well. Once it is run in, it should get maybe about 550-600km/tank, better on freeway cruising.
I'm not sure how long it'll take to loosen up, but my guess is about 5000kms. My dad ran their car in pretty gently, with occasional bursts to help bed the engine and other components in.
I guess the best way to run a car in is to drive (relatively sensibly) in normal traffic with plenty of start/stop driving instead of monotonous freeway cruising, eg great western highway/paramatta rd compared to M4.