I've used mother's milk tea successfully. You can sweeten it with Stevia. You also need to drink, drink, drink - if you're going to the bathroom 30 minutes after you drink, you're completely hydrated (which your body needs in order to make milk).
I couldn't pump 4 oz if my life depended on it - never could. Despite that, my babies had pinchable cheeks and chubby thighs way before they had solids. My breasts just didn't like the pump.
Most of the herbs that are recommended to increase milk supply are liver cleansers. Not sure about the relationship, but beer has been shown to reduce milk supply - so maybe the liver is more involved than one would think.
Are you on any special diets (specifically weight loss, low carb, or vegan)? Any of those can alter your production.
S.