Go and check out the spinning babies website (www.spinningbabies.com) - lots of great tips on how to get bubs into a prime position for birth. I know it would be hard with a cold when all you want to do is lay down in bec, but try to sit upright (sitting on a dining chair is good for this), no slouching or even laying on the couch if you can avoid it and don't sit with your legs crossed as this apparently opens up the back of your pelvis more than your front, meaning that it is easy for baby to get into the posterior position easier.