I think the people from the Czech Republic is who Walt is about to fight in the flash forwards. They're fed up with the purity being so low and steal someone that Walt still cares about. (I'm pretty sure Gilligan said during the first 8 episodes that the Walt was getting that gun to protect someone he loves). No clue on the ricin.
Man, that garage scene. Once the garage door closed I was on my feet the whole time.