How long are you pumping? And how often? I know you don't have time to pump more, but having that info may help us figure out if it would be possible.
Have you ever tried power pumping? You've nursed, so you know very well the cluster feeds that occur during growth spurts that boosts supply. When you pump, you don't get those cluster feeds. So, unless you artificially emulate them, you might not get the desired increase. Make sense? There are a few ways to do this, even if you are very busy. You can take an hour a day for a few days where you pump 10 min, rest 10 min, pump 10 min, etc... For an hour. Even if you're not getting anything you are telling your body to make more. Others just take 2 days and leave the pump out and pump as often as possible, even if for only a few minutes. Even pumping longer during just 1 or 2 sessions a day for several days could make a difference. Just think back to those early weeks of nursing and how much time you spent nursing during those growth spurts. Also, make sure to pump during the night if you aren't already.
Have you thought about trying a manual pump so you can be more flexible in your pumping routine? You can take the pump with you when you are sitting on the floor playing with Addy or even in the car. Good luck!
What pump do you have? My ped told me the Medela Pump In Style is THE best pump available and will get the maximum amount of milk out.
Have you tried the "supplemental feeding" system. My baby won't stay latch on unless he is getting something. So, at the hospital they gave me this little tube I attach to my breast and goes in his mouth...your fill a bottle with "breast or formula milk" but the tube on your bube and into his mouth and voila...he is drinking and stimulating your breast at the same time!