The saddle you choose needs to be WIDER than your sit bone measurement. In an ideal world, your sit bones would each land in the center of the "cheek" of each side of the saddle.
If you call Wallingford Bicycle Parts 1-888-731-3537 Bill or Diane will answer the phone (unless they are crazy busy)
Tell them what your measurements are, what bike you ride, and how you feel on your current saddle. They will be able to steer you toward a couple Brooks saddles that might work for you.
They are full of knowlege, and don't be afraid to "girl talk" with Bill. He is VERY cool, and understands women's saddle issues. He also won't mind a bit if you ask that Diane call you to discuss girl issues.
They are both great. Call them.
(and no, you shouldn't be weightbearing on anything but your sit bones. Is your seat to high or your handlebars too low, or your posture goofy? Or is it the saddle?)
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson