Anthony,
That sounds particularly bad, but town riding wont get you far mileage wise. Picked mine up in Brisbane and the seller told me 200k before the light comes on regardless of how it's ridden. He was dead right. That's about 17ltrs. Now with the Microtec from Chris at XBikes and a good map I get 250k before light comes on. They have shit mileage standard. Change of air filter/exhaust can make a big difference but comes with the downside of needing a possible tune which is nigh on impossible with the std. ecu.
You might strike lucky, fit an Arrow or something and it'll run o.k. You will probably have issues in some areas though. Trust me, I've been down all these roads. A Microtec with a good map transforms the bike to what it should have been from the factory. Expensive but worth every penny, performance and mileage wise.
Cheers
Deano