I redeamed a itunes card on my ipod touch, but it doesnt show up on my itunes on the computer.?

so i redeam a itunes gift card on my ipod touch under the itunes section and whn i get on my itunes on my computer and it says i don't have any money on my account. i don't have wifi at my home so i can't use my ipod to get songs/apps. what should i do?