It´s deffinately not a Dogo Argentino because they have very short hair as pups..they resemble dalmations (short coats,white,stocky etc).I know because there are ALOT of them here and it happens to be one of my faves Heres one so you can see:My Sister Was Told That She Is 2 Weeks Old When We got her On Last Saterday. And I've been doing Some Research N Lookn At Some Pictures, To Me It Resembles A Dogo Argintino(Argentine Mastiff). But A Freind Of Mine Told Me That Her Paws Are Small And She Couldn't Grow Up To Be a Big Dog.
This/your pup has fuzzy hair,like a 2 week old husky would have.It´s paws are also very small,so I´m guessing its a medium/small size breed what ever it is.Is she a mix? How come your sister has puchased a dog yet doesnt know what she is? Disnt she see the parents or at least the mother?