I am attaching some links which I hope will be helpful.
From a personal perspective I suffered postnatally with PGP and SPD after the birth of our second baby and had recurrent bouts each month until I found Birthlight and Spinning Babies and was very grateful to learn the techniques which relieved the discomfort I experienced each month. Within a few weeks I was pain free and now lead a pain free life each month.
http://www.birthlight.com/page/pelvic-girdle-pain which has links off to a couple of important pieces of information.
You may want to consider Aqua Yoga which I also teach on a Thursday evening