Can only do 40 seconds on one track

I was messing around with garageband throwing loops in the track and does it only give that much time or is there a setting where i can set the maximum time? Im really new to the program so im learining the ins & outs to it. I believe that you open a new track if i was to record from line in correct? Thanks in advance

It's been a bit since you've posted this, but just in case you still need the info.

At the very top of the track window, you'll see markers (either beat or time depending on what you've selected). If you scroll over to the right, along that line somewhere you'll find a purple arrow pointing to the left. That little guy is the signal to end the song. Move it over to the right to your heart's content and you'll be able to make longer songs.