Need Help: What will be the Aqua 2013 fuel consumption in my driving requirements?

I want help from the Aqua owners, the suggestions and opinions will help me to get rid of the problem and will help me to save money and time. I have come to know that two passengers can easily sit for going to long tours on the rear seats of Toyota Aqua. I am going to tell you about the requirements of my journey and driving conditions so in this way I will be able to understand that if I buy a Toyota Aqua what will happen. I am freelancer and working with USA clients for last five years. I am a software engineer and working with USA clients from home.
My City Driving Conditions:
I have driven my car for a short distance to chowk from my home which is the distance of around half kilometer. I drove with the speed of 20-30 km/h. Then I went to the main market while driving my car which is 2.5km far from my home. I drove the car with the speed of 40-45km/h and covered the distance of 2.5km to go to the market. The total distance becomes the 10kms by summing up the 6kms on both sides. My total city drive with my car is 1200-1500 km/month as used to go to the main market 2 to 3 times a day.
Big Question:
Now I want to ask that what average i will get in city driving in my given above driving conditions? I have read online that Aqua Prius C is made for city driving. I expect 20-23kms/l average in above conditions. My Vitz 2013 gives 10-12km/l with AC and 13-15km/l without AC in above mentioned conditions.
Motorway Driving
I go from Multan to Sahiwal o r Okara 2 times in a year. The travelling distance is 450kms of both sides. On motorway my Vitz gives 15km/l with AC 5 people on board. Without AC it gives 19-20km/l I will spend 4 to 5 lacs to switch from my Vitz 2013 Grade 4 to Aqua 2013 Grade 4 car. My goal is to buy Aqua for fuel efficiency so that i can run Aqua as much as I need. I don’t want to go while driving motorcycle anymore due to safety reasons.