The sippy cup sounds like things are going about par for the
course. It just takes a while for them to catch on to the sippy cup.
As for the puffs, I would hold off on those until your daughter is doing well with stage 2 foods (that have little chunks in them). Then I would put a few on the table in front of her and let her feed herself. Sure, it gets a bit messy, but it's great entertainment both for you and her.
I presume that you have already started her on cereal, applesauce, and the like (stage 1 foods). If not, I would go through all those first and then move on to the chunkier stuff. Cheerios are also great for teaching coordination and they're significantly less expensive than the puffs...with a similar consistancy.