To store pull it up in sterile syringes and store in the fridge.
As far as dosage is concerned, it's according to how it is supplied i.e.5000iu/ml, 2500iu/ml, or 500iu/ml. If 5000iu is one ml after reconstitution, then 1/2ml is 2500iu and 1/4ml is 1250iu. The easiest way to dose is like Manbeast suggested. If you have 5000iu/ml add an additional 9ml of bacteriostatic water, and the end result is 500iu/ml. I usually pull up 1ml in ten different syringes and put them in the fridge. My understanding is that they will last up to 6weeks in the fridge. Just remember to shake them up a little before using them.