Vauxhall vectra diesel Electric Suddenly Stoped?

Car was runing ok, Battery light was showing up, Just put a new heavey duty battery a year ago, Whilst travelling radio & dashboard light went off, Head light & Indicators light were working, Was having problems in statring the car for 1st time during the day, there after did not expericne any problems in starting the car during the day, I would go through the same process during the following day. HELP. I am very fond of Vectra Disel V reg. i would like to get extra year use out it