recording unexpectedly stopped in garageband

I was recording the first part of the Ring Cycle from the Proms yesterday evening, from my radio tuner into GarageBand via a Belkin RCA Audio Cable into the 'audio in' port.

I selected a 'basic track' and set the tempo to 80 bpm. The broadcast was 2½ hrs long, and I understood 80 bpm should give me somewhere between 5½ hrs and 11 hrs, which should have been more than enough time.

However, about 2 hrs into the recording it suddenly stopped with a message something to the effect that the file capacity of 2GB had been exceeded.

But when I clicked the 'record' button again, it nevertheless continued to record.

The next opera in the Cycle is this afternoon. If someone could present a solution before then, I would be extremely grateful !