VOLVO 850 COOLANT LEAK

For the last three weeks my coolant light has been coming on. First it would flash on and off, then became steady. I keep putting in coolant but can't tell where it's leaking. May or may not be radiator. The needle never goes past the 3:00 position, but today it started to overheat for the first time. Since my mechanic is 75 miles away I wonder if it's safe to drive there as long as I add coolant when necessary.