Warm baselayers are one of the 'Must Haves' for any woman who rides year round. It really does make a difference!
Above left is the Schampa skinny shirt (matching pants also available). Read my review here.
Above right is the Icebreaker Merino Wool zip top. It's on sale from Backcountry Gear for $75. I've heard great things about Icebreaker clothing. If you know someone who can't afford to buy a whole new set of insulated, armored gear, this might be a great accessory in the meantime to help keep them a little bit warmer and more comfy.
Unfortunately I don't know what the fitment is with the Icebreakers, but I did stumble upon a travel forum that had some comments implying that they're curvy friendly in terms of shape.