I feel your pain. I just camped out in 30-knot Falkland Island winds in a battered 20-year-old, what-used-to-be-down mummy bag and the cold made me crazy. In my disoriented slumber I thought the penguins squawking outside my tent were actors in a British sitcom.
GoLite just came out with the Adrenaline O, a beautiful zero-degree, 800-fill goose down, gender-specific bag designed to bring warmth and comfort to the places women need it most. For side sleepers like you theres a center/front half zip that eliminates cold zones on the side of the bag and also keeps you from being impaled on a zipper pull.
With a snug hood and a 50/50 down distribution for full loft and warmth, this two-pound, 10-ounce bag will keep you so cozy that you might want to consider it in the 20- or 40-degree version. $400; golite.com.
Depending on your height and weight, another good option is the Rab Womens Atlas 750 bag. Shorter than a mans bag (200 x 70 cm), this ten-degree, highly breathable, highly abrasion-resistant bag was designed with a narrower shoulder area and wider hips, which better mirrors the shape of a womens body. The 600-fill, three-pound, five-ounce bags shaped hood and two-way side zip with a down-filled zip baffle ensures that you arent going to get an arctic blast in the unfortunate event that you have to readjust your zipper in the middle of the night. $325; rab.uk.com.