Where can I get a sonogram without getting a mammogram first?

I haven't had a mammogram in years, and have had severe pain for a month. I have no insurance and very little money. I've read recently that mammograms don't do as good a job of picking up cancer, but that sonograms do better. I was told by Eastside (Emory) Hospital that I can't get a sonogram unless I've had a mammogram first. The mammogram costs $130 + radiologist fee, and the sonogram costs $300 + radiologist fee. I didn't pay my mortgage so I could pay these fees, and I'm sure that once I've had the mammogram they will want a sonogram also. I have no income after October, so this is an extreme hardship. I can feel the lump and the pain is in a very specific area, so all they need to know is where it is to do a needle biopsy. Where in the Atlanta area can I get just a sonogram?