iTunes Downloading Problems

Gosh, I do seem to have my little issues with iTunes. Perhaps my
computer is just getting too old for iTunes. Hmmmmmm...

But I digress. What is happening is that a few of my podcast downloads
are cutting off before they are finished. I know it isn't the fault of
the source because my husband has two of the same podcasts in his iTunes
(on his iBook) and his downloads were complete. I wonder what might be
causing this.

We have high speed DSL and Airport Extreme wireless. And we're all on
Leopard now (but this happened sometimes in Panther too). I wonder if
it might be that the Airport card in my G4 Quicksilver is less reliable
than the AE cards in our other two computers. Any ideas?

And question #2: How can I go back and download just the incomplete
episodes into iTunes? I know I can play them right from the iTunes
store but I want to get them onto my iPod. Thanks.

Madeleine