Abscessed teeth with drainage and calcification.?

I have 2 teeth that are abscessed. Doc. drained and says that the infection is so severe that the old pus that has not drained seems to have calcified. No dental insurance and having trouble getting them pulled. Is this serious? What should I do? All of the antibiotics they have given me aren't working. I have already lost a thumb to MRSA and I am scared that it could come back and get into my jaw. Any help would be wonderful!!!