A.M.
the day care should not be throwing any of the milk out. If you have a little more than you need for one day, it can get used the next day. Here is how I did this. A baby needs approximately 2.5oz per lb per day. So calculate what this is and divide it by the number of feeds you usually give baby per day. Then work out roughly how many times during the daycare time that baby will be fed. So you then calculate roughly how much the baby will feed and send that amount or slightly more to daycare. I would send it still frozen. They can thaw it out as needed. That way if there is a little left at the end, it can be used the next day as it won't have been thawed all day.
Pumping will decrease your supply a bit but what you can do is nurse the baby a bit more to get it up and the weekends are great for this. everyone is different as to how much they get from pumping. pumping early in the morning gets you more compared to later in the day. drink lots of water too.
Also remember, it isn't the end of the world if baby gets a little formula. The more you nurse, the more the supply will come so if you notice a dip, try to nurse at home more.
good luck.