Headlights

I own a 1997 Toyota Camry 4 cylinder. It has had no leaks and no major repairs apart from a timing belt being replaced. Recently, I was driving and the battery light came on. I stopped and cut the car off and tried to start it. Everything stayed on, but the car made a clicking sound as if it needed a jump start. I replaced the battery and when I did, only the headlights on, but nothing else (the tail lights, door locks, dashboard lights, etc.) Would come on. I had to disconnect the battery to keep it from dying. What should I do about this problem? Does this require an alternator, or could it have something to do with a loose connection?