Re: back to work...lost when it comes to pumping!
Mostly agree with PP, just want to add that if you pump at the same time when you work your body will get used to a demand at that time, which can help your output. Pumping both sides at once will also increase your supply/output, which seems like a good thing for you now.
Another bit of advice - if your mom knows you're getting home in an hour or a half hour, have her try to just give 1 oz so that you don't have to pump again at 3 am And to echo PP, 3 oz is the normal bottle size for a little baby (all the way up to a year, actually!). Give 3, try other soothing, then give 1-2 more oz if baby still is hungry. can't link now but there's an article on kellymom.com on bottlefeeding the breastfed baby - you might want to look at that and talk to your mom about it.
Nursing, pumping, cloth-diapering, babywearing, working professor mama with the awesomest SAHD ever.