Did you check to see if the alternator belt was tight? If it feels loose, then I would suggest tightening it and see if the lights go out. Do you have a multimeter? If so, connect the multimeter (make sure to set it to read DC volts) to the battery and run the engine. With the engine running, a good alternator will put out about 14 volts. If it's less than 13 volts, then the alternator definitely needs replacement.