Bro, if you want fuel efficient car, then go for used JDM Vitz, Passo / Boon in 1000 cc category, or hybrid Vitz, or Aqua in 1500 cc category. Swift AT is not fuel efficient when compared to these JDM cars.
I have upgraded to 2015 model Vitz, and MA SHA ALLAH, it is giving me 18~19 kmpl + average within city (without AC).