Dette var jeg ikke klar over…..
I think the sleeping bag is okay. You could add a liner to it, such as the REI Lightweight Fleece Bag Liner ($45). That extends the comfort range by ten degrees or so. Then, fix her mattress. If she has a true air mattress, then she has almost no insulation under her, just cold air. So do one of two things. Either swap it out for an insulating pad (Exped DownMat, which is a down-filled air mattress, $130). Or, throw a light foam insulating pad over the air mattress. Cascade Designs Therm-A-Rest Z-Lite ($29) would do nicely, adding several R of insulation values.