I would check your wiring harness. It almost sounds like there is a loose or corroded connection coming from your alternator. With your radio dying then coming back on that would suggest that your power from the alternator and baterry are fluctuating. If the car died when you turned on the head lights or a turn signal they may have taken the last bit of power required to keep the car running from the alternator. Check the connections from the alternator and also follow the guidelines in either a Haynes Manual or Bentley to test your alternator.

Hope that Helps.

Keep posting, you'll get it fixed.