Situation with this puppy? help!?

Raising a puppy correctly takes a lot of work. You mentioned you already have a Staffy with some issues that haven't been worked out. I'd suggest you, in fairness to the puppy, find the dog a new home. Now if you decide to take your Staffy in for some training to resolve her aggression, and take this puppy to training cles also, then go ahead and keep the pup. Otherwise when the puppy gets about 4-5 months old, you will probably find you Staffy getting aggressive to that dog also and the Staffy can kill the young dog. Don't be fooled by the Staffy being tolerant of a 12 week old, that will change as the dog ages.