What can I use instead of my car?

Since I've been tracking my petrol usage on the Carbon Diet, I have realised that in the last 6 months, I have only used 3 tanks of fuel. The car is a 2-seater, basically just for me, no use for the family, and these days I never use it. I spent more on tax, insurance and servicing than fuel in the whole of the last year. It hardly seems worth having it.

So, considering I live out in the countryside where the buses don't run at useful times, commute just once a week to the station 10 miles away, but want to be able to go 20 miles to Guildford and back reasonably quickly from time to time without leaving my wife without a car, what can I replace my car with that is more environmentally friendly? Ideas, anyone?