I'm very sorry to hear about your loss. I know how hard it can be to lose a friend like that.
As for what to do now, I think it depends on the person. I'm the type of guy that has to be occupied all the time. I have to have something to do, sounds, etc or my mind starts to wander real bad. I guess for me I would prefer to have a new puppy to work with than to sit and do nothing. I know it's hard when there's so many similarities in the dogs, but I think once you get started with one it will quickly distinguish itself with it's own personality and quirks.
So that's what I would probably do. It doesn't mean it's the right thing for you, but hopefully it helps some.