Ahan nice question paper 
I know I will fail if I attempt. But I should try. I know soon experts will drop in to tell you more. But just take it as a starter. Herez what I know:
Whats the tentative price for garde 4.5
I have not seen a 4.5 grade car. But I have seen alot of 4.0 grade rides. They identify it with two genuine keys.
In Islamabad people are asking 10.3K to 11.2K for 1.0 and 11K to 12.5K for 1.3L. Frankly speaking, "jis ka jo da lagay" wala hisab hay 
This is the price of 2007 and 2006 versions. 2008 to Allah moaf karay agar kisi nay import ker li hay to 13K say kum mang hi nahi raha (I have just seen one in Islamabad, Main us kay qareeb bhi nahi gia :P)
Whats the avg milage over petrol within city with AC with normal driving.
People claim 17 to 20 in new shaped vitz 1.0 as it is only three cylinder. Reality to chala kay hi pata lagay gi 
Doe Echo/Hbrid play role for fuel efficiency.
Obviously it should play a good role theoretically. I have never seen a Hybrid version. The ECO version is available. I dont know how much change it will bring in.
Does Echo/Hbrid mantainance expensive as it involves extra dry batteries
Well ECO works with extra batteries but I dont know much about it.
Does GPS works in Paksitan
Yes GPS works every where in the world. All what you need is a device which can extract geo coordinates from satellite and the updated maps. Many companies are giving such devices and maps. You can buy any Garmin device. or you can go to some company like tracker.
Navigation In Pakistan
What are the diff between 2007 and 2008 model.
I dont know 
Spare parts availibility.
They are available easily but are very expensive relatively.
comparing it with Honda City what are the features.
Cons of honda city
Honday city is expensive in terms of first purchase. It is a sedan. It has 1.3L version only (but its sedan). The automatic one is even far more expensive. Registration is expensive. Mileage slightly lower. Interior looks a bit cheaper in quality. No headlight adjustment. No push start. No retractable mirrors. No rear viper. No Safety features like SRS bags. Less comfort because of hard suspension
Pros of honda city
New!!!! Sedan. Stylish. Class. RPM Meter in every unit. Parts more easily available.
Or kuch yad nahi a raha.
Have I passed? Come on as a new comer u should give me some fever
regards,
