I have the same problem as you before. I was really obssessed as I don't really have lunch time, every time when I pump, I have to stop everything and I can't even answer any phone call. So helpless at that time as what I can do is just waiting for the second and third "stimulation response".
I finally bought a Avent manual pump (I am using Swing orginally), and I can pump the same amount (4-5 oz.) for 10-15 minutes. If I am not busy, I can wait for the second and third "stimulation response", so that I can get extra 1-2 oz.
Try this method, buy one more pump and you can save a lot of time.
I have the same problem. My baby is almost 4 months and I could only express 4oz in one hour. If I just pump 30 mins, I may have only 2.5oz. But my baby needs 6-7oz each time. I try to use 2 Avent manual pump at the same time, it makes no difference with using only one pump. That means I still need 1 hours. How can I express milk faster?