I agree about agnus castus. It did not help me at all and I suspect made things worse.
I was lucky and was being treated by a gynae for my fertility issues and by an endocrinologist for PCOS. The endo I see is very interested in PCOS and the link with diabetes and she runs a specialist clinic for PCOS women.
I was prescribed a mega does of metformin and was told that it is more effective than clomid in women with PCOS. However, at the same time I had something called ovarian drilling, which is exactly what it sounds! This kept me off work for a while due to a post op infection and I maintain it was a combination of the metformin, the drilling and work avoidance that got me pregnant (apart from the obvious!)
What does work, as hard as it is, is losing 10% of your body weight. The most effective way to do this is to take metformin and follow the low GI diet. I continued to take metformin during my pregnancy on the guidance of the endocrinologist, as it helps to reduce the risk of miscarriage and gestational diabetes.
I feel so much better when I take metformin, have a good diet etc. I have more energy, my skin looks better and I actually ovulate. It is true, you can't take your temp really but what you can do is look for cervical mucus. You need to be on the look out for the clear, stretchy egg white looking stuff, then go for it!
It is possible to get pregnant, but aside from the pregnancy issue you do need to get it under control for future health protection. I really am pot calling kettle black here because I haven't taken my metformin for a while (got out of the habit) and my diet is all over the place but I am getting better.