Go with the spacers, never go with coil springs unless a height increase of more than an inch and half in required. when ever you increase the height of the car with spacers/springs the 'Center of Gravity (CG)' is disturbed which is not good in case of emergency braking, turning in high speed and sudden tire bursting at high speed.
Increasing the height by an inch or an inch and a half wont matter much.
Changing the rim size from 12'' to 13'' wont disturb the fuel economy much just be care with tire width, stay within the manufacturers recommended tire wide and height (usually found on the sticker on the car frames center pillar on the driver side). Installation too big and too high tires definitely cause high fuel consumption, suspension wear and tear, poor braking and CG problem.