This is a good site on storage, and you can buy breast milk storage bags. You can freeze milk in them as well.
3 to 5 days in fridge 6 months to a year in freezer. Keep in mind not to store in the door. Keep them in the back and the center, temperature is the most stable there and that'll keep them from going bad faster. If you can find breastmilk trays (pretty much an ice cube tray designed to freeze breastmilk) you can pop them out of there and store in a freezer bag. Thawed breastmilk is good for 24 hours and you can't refreeze