For a budget of Rs 5 lakh, there aren't many automatic new car options available.
You could opt for a Maruti Suzuki S Presso VXi AMT, which would serve your needs. But as you need to carry four family members during your occasional weekend use, we would recommend upgrading to a Maruti Suzuki Celerio 1.0 Petrol VXi AMT. It is a bit more spacious and upmarket.
However, yes, given your limited usage and need for passenger room, we would recommend checking out a used car

