Some suggestions on two-wheelers required

My father had bought an LML Vespa NV way back in 1991, and it performed well enough till date. But since last few years it has started drinking fuel like anything. I guess our maruti 800 gives more mileage than this machine.

So daddy needs a new two-wheeler. Please suggest some.
Budget :- around 50,000.
Mileage:- the more the better. (obviously)
Purpose:- just a daily ride of approx 10 km up and 10 km down. (office)