You can drill it out or use an "easy out" (drill a hole, insert EZ out and turn it out) but whatever you do - don't drive it until you get your new bolts. You'ld be playing "russian roulette" with your new brake parts driving without that hold-down bolt.
I know of people who have driven with them out - but with heat, expansion and the width of lug bolt threads there's a possibility of the rotors "flexing" under braking and it's not worth the price of your work & $$$ taking the chance.
