A.Y.
Do you pump during the day because you work? If so, then I'd nurse him as often as possible while we were together. The boobs don't respond to the pump like they do the baby, so it sounds like they aren't getting the hint that they need to step it up a few notches.
I ate oatmeal while I was nursing because that's supposed to increase your supply as well. It's only supposed to be the regular kind, not the instant, though that's what I ate. You can also eat oatmeal cookies, too, and see if that helps.
I will also recommend the website breastfeeding.com. Go to the general board and you can receive some great advice there. They also have an archive of common nursing problems that would be worth looking into. The book "So That's What They're For!" helped me out on many, many occasions! They have it at Half Price Books for $4, usually.
I hope this helped you some. I'm not a lactation consultant by any means, but I nursed my daughter while working full time and pumping three times a day. I know it can be tiresome and stressful, but you are doing a great thing for your baby. And don't feel bad if you have to supplement, but do realize that your supply may drop even more if you do.