caitlyn,
Do u own any OCBC credit card?
U can opt to pump ur petrol in SPC, whereby you can have a 3% rebate on top of the normal 10% disc. That is how u can save on petrol cost.
As for getz, i think full tank can go abt 350+km, i am not so sure, but can help u to ask my frenz or cousin, they own a getz.