How do I clone the MacBook Air hard drive?

I want to upgrade our Macbook Air original A1237 80GB hard drive to 120GB. I have Superduper and a 2 1/2" (I think that's the size) hard drive cover I've used when I upgraded our 2 iBooks to clone the new drives. I haven't got the new 120GB ATA drive for the Air but I'm afraid it won't fit.

Is there an external cover for the 1.8" Air ATA drives that I can purchase, and if so, where do you recommend?

If not, how would I clone the original drive to the new? I've got an USB external hard drive. If I clone to that how do I then clone to the new 120GB drive?

I also asked Shirtpocket what they recommend using Superduper. I'll post whatever they recommend. Thank you.

I know the Air upgrade will be harder than the iBook but I'm confident with the ifixit step by step and your help I can do it.

Thank you.

Mark