PCOS and weight loss.

I've gained a lot of weight starting from puberty. I was told I have PCOS. I use to lose weight really well. I lost 25 pounds and a month. Now I just pack it on. At this rate I will be 250 by 2016. I was hoping if anyone found a good way to lose weight with PCOS. I'm 229 right now and want to be down to 140. I'm 5'2. I was hoping I could lose it before August but every time I try it seems I'm gaining more weight.