How to get money on your shopping card on animal crossing wii?

I got a shopping card and I went to go use it at Gracie Grace but they kept saying I didn't have enough money to buy anything. My question is how do you get money on your shopping card and how do you use it?|||The shopping card is linked to your Animal Crossing Bank account. You need to put more money in it. By the way, The only place you can use it is in Gracie Grace.