How serious is a MRSA staph infection?

I've heard that it's caused more deaths recently than AIDS! It seems like healthy people are dying all over the country. I have MRSA in my bloodstream. I'll get a pimple or a boil and it'll get really infected. I've had about a dozen infections in the past year but haven't had to be hospitalized yet because I haven't had a fever. My most recent infection was in my knee and it spread throughout my leg and it swelled up like three times the size of my other leg! Steroids took care of the swelling. I take Septra but it doesn't seem to help work because the MRSA is still in me. I pick at my sores (it's part of my OCD) and I've tried to stop because it makes it so much worse. How much of a risk do I have of this getting into like my lungs or brain or somewhere serious? I'm 34 and am in moderate health otherwise. Also, am I at risk of spreading this airborne? And if you know, how rampant is MRSA right now, are they blowing it out of proportion? Thanks.