Hyundai is known for its diesel engines and the Verna's 1.4 crdi engine is also good in every term. There is a lag till 1750 rpm, but it is not that evident. The car perform well in all manner but the suspension is not that impressive.
As touchscreen infotainment system and co passenger air bag are completely dependent on the compatibility of the vehicle whether it can be fitted in your car or not, we would suggest you to contact your nearest service centre. Click here to fetch the information of the same.
The first mandatory service for the vehicle is due on 1000 kms which includes the oil change. As you have mentioned in your query that the Verna is driven nearly about 900 kms, so it would be better that you take the vehicle to the service center for the first mandatory service. We strongly believe that it would sort out the problem that you are facing currently. If the same problem persists, even after servicing and oil change, we would advise you to consult with Hyundai workshop engineers, they will sort out the problem for sure.
We also request you to read the article, which will help you to achieve better fuel economy. http://forum.cardekho.com/topic/356-how-to-increase-mileage-of-your-car-tips/