Like teevee247 mentioned, remove the driver's side wheelwell liner.
(It's impossible to remove the metal fender without opening the hood.)

Assuming the hood cable hasn't been relocated by a previous owner, you'll be able to lock a set of Vise Grips onto the broken cable and open the hood latch.

When you replace the hood release cable, you may want to re-route the cable through the engine bay instead of through the wheel well.. This will make it very difficult for thieves to open the hood from outside the car.