1982 Fairmont Futura won't Start, Battery or Alternator?

My car wont start unless i Jump it. If i try and start it when its not jumped, the Ciillinoid just makes these weird almost like grinding noises. If i hook jumped cables up and jump my car, it starts right up. Last night we jumped it and i got about 5 miles down the road and the car died again. Had to have someone come jump it. Is this the Alternator or a dead battery? the battery is only about a year old.