Choosing How to Pay for Items in iTunes

Hi,

For an early Christmas present, I just got a new iTunes gift card. (I love those things!) One thing I've been wondering for some time now is after redeeming it, which I've already done, is there a way I can pay for something, such as an in-app purchase, using my credit card while saving the iTunes balance for something else?

Thanks.

Yours Sincerely,
Kelly Sapergia