Noises in lower gears are, generally speaking on other similar gearbox types, caused by the input shaft bearing nearest the clutch. Topping up the oil level is an absolute priority as jrkitching said. If the correct FIAT/Tutela oil is not readily available, a semi-synthetic gear oil with GL4 rating will suffice - better to have something in there quickly even if non-genuine.
After that, if the noise persists, it will be worth repairing or replacing the gearbox before a possible complete failure, especially on a nice low-mileage car.
If there is any clutch shudder, that could be a sign that the input shaft bearing has failed in a significant way (either to leak oil on the clutch or to cause misalignment of the clutch) and requires urgent attention.
Sorry if all this comes across as alarmist.
-Alex