I picked one up through the Hasbro site as long as I was ordering
I did the same - I picked up the Artoo-Potatoo when ordering my GH 2-packs (and he arrived yesterday).
Artoo is a bit smaller than the other Potato figures, which makes sense I guess. And he doesn't really have as many parts as the others, but at least he's got the mini-Holo figure which is cool.
I'm still not entirely sure why I'm buying these potato guys, so I guess I could go either way. If they do make the eventual Obi-Spud Kenobi or Luke Frywalker, I'd probably buy them, but if this is the last one, that's cool too.