^ Good call Patrick - OP it really depends on what you are doing or not doing when the symptom occurs. It may or may not be the clutch throwout bearing. Just because the shop told you it was I would still make sure using my own common sense and diagnostics and see if it is or if it isn't. Do your own checks! You auto or manual? Does it do it all the time or only when you press the clutch in, or when you release it or when? Does it do it only in a certain gear, or when idling in neutral? Where is the noise coming from?? We need more info to help you.. but best of all use some common sense and trouble shooting techniques and figure out what it could be yourself. Just saying 'i heard a squeak and the shop told me it was a throwout bearing' is extremely vague. A squeak could be anything..
If you're sure your shop is right and it IS the throwout bearing, you can drive on it until you can't engage your gears anymore. Then I would recommend replacing that, and the clutch itself, best bet is to upgrade to a better one along with a performance flywheel.