I realized my redemption card expired about two days before my trip (there was no money on it--the card just expired). I picked one up in the parks, same as Girimama. They have the redemption cards at City Hall in DL, the Chamber of Commerce in DCA, and at the Guest Services location in the esplanade between the parks. (I got it at Guest Services so I didn't have to use park time to get one). They will ask to see your VISA card and your ID. They give you a card, you call the number and they will load up however many reward points you want on it. At that point, the card is ready to use.
I never load the full amount at once--just because I'm never sure we'll use them all. It's VERY easy to call the 800-number and add more points onto the card, and they're available instantly.