First off, I have to mention that if you are under medical care and doing any sort of drug therapy, please do not take herbs until you've cleared it with your doc. I know you probably know this, but had to say it.
Ok, if Clomid worked for you, then Vitex would probably be the best place to start.
http://pcoscoach.com/vitex.html
Of course, one of the sticky things to keep in mind is that you may have a couple of things wrong with you that need attention and taking only one herb to handle one problem may cause another to pop up. For example, if you take False Unicorn Root, it will help with ovarian function BUT it's a drying herb. So if you have issues with CM, you could compound it by taking FUR. Does that make sense?
Honestly, I would suggest going to a licensed herbalist and seeing what they can put together for you. There are tons of options really but you need to know where you fall in the whole scheme to make the proper decision. The book "The Infertility Cure" has a chapter on PCOS. It's a great, great book.
And finally, probably the best thing you can do is go on a low carb diet. Ladies with PCOS can show great improvement just by getting rid of the refined sugars in their diet (of course, you're probably already doing this. Just thought I'd mention).
I guess I wasn't much help, huh? But the Vitex really is an excellent herb. And has helped many of us get those precious bundles!!