brake caliper bleeding screw

[ercp98]

i was trying to bleed the brakes. i ended up braking off the bleeding screw / nut but i did not loosen it. i think the caliper is a remanufactured caliper already. it has the 8mm nut and not the 10mm nut. how can i fix this? can i just drill it out and put a new one in? or is the caliper fubar already? can i replace it with the 10mm nut?

thanks for any input.