Dwest,

The way to remove this is pretty simple. If you have access to a dremel tool, I would cut a slash on the exposed bleeder screw, then use a flat screw driver to twist it out. If there is no expose screw left, I would remove the caliper and take it to a machine shop. They should be able to drill it out. I would wait until this is fixed, then bleed the system at the same time. As for changing brake fluid, I would recommend doing this at the recommended interval, contrary to others.

Hope this help,

John