Just looked into this further. It may be easier and cheaper just getting a laptop-specific card.
SDIO devices, although using exactly the same socket contacts as an SD card, probably won't interface to your laptop, via USB ard reader, in the same way that an SDIO slot on a PDA would work. The contacts are the same but different things are being sent down the wires - from what I understand.
Best to check all this with the manufacturer though...