Pumping/storing milk.....?

I'm trying to pump a little in between feedings so I have some on hand if I need to leave my baby with my family. I need to know how to store it though?? And I am only able to get a little at a time as my milk has just come in. Is it safe to pump a little into the container, refrigerate it, come back a while later and pump more until its full and then freeze it?? What's the max I can keep it in the fridge and do this? Also, when how do I thaw it out for the baby and how warm should it be?