Considering the budget and fuel economy, you should opt for a 660cc car such as Alto PKDM/DJM, Mira ES, Nissan Dayz or EK wagon. I would prefer either Mira or Nissan Days/EK wagon (they both are same with different badges), their fuel average is between 16-20 kmpl within a city. Search on Pak Wheels and may find the one within your budget. Plus, the AC performance is up to par in the mentioned DJM units.