I wasn't able to pump a LOT until closer to the one month mark. I think I hit a record high around 6 weeks... according to everything I've read the height is usually around the 6-8 week mark, so that makes sense to me! In any case, since around the same time my baby's mouth has grown large enough so the latch is no longer a problem. Now I only pump 3x per day (once in the mid-morning, once in the late afternoon, and once before bed) and I get 7-10 ounces each time I pump. I feed her from the breast half the time and from a bottle the other half -- this is perfect for me as I've been able to start a nice freezer collection for when I start weaning her off the boob and am working again.
I've written about it before, but what worked for me was increasing my milk/dairy intake and getting rid of products that cause milk production to drop (as a vegetarian this meant cutting out soy products mostly, but also no peppermint and reducing the amount of things that would cause dehydration). I drink A LOT of water --- 1.5-2 liters, including while I'm pumping in the morning and at night. I also have tea made for breastfeeding that contains anis and fennel. Since I am not a big eater, I try to get my calories and milk-producing products all at once, i.e. cheese lasagna, salad (vitamins!), half liter of water, and an ice cream bar for dessert.