fifi1puss is right.
We have seven cats, three of them female. The oldest one, Spooky was only - three? - four? when we adopted Ming Loy. It took her a full six months to stop hissing when Ming Loy got near, and a full year before we saw Spooky grooming her.
In our experience, females bond more closely to individual people than males, and get VERY jealous of other cats intruding on that relationship. Male cat intros always go far more smoothly for us as it doesn't upset the girls as much as bringing in another female.
The age difference of 6 and 12 weeks is large, and (kind of like bringing home a three year old to be friends with a 30-something year old person) it could also easily be Dusty just isn't into all that energy.
I don't know your situation - but at this point, maybe it actually makes sense to rescue another younger kitten (a male!) so Squeak has somewhere to direct all that energy, and they then won't bother Dusty as much.
Otherwise - yes, a week is WAY too early to expect them to be friends. In our house, with the girls becoming friends with a girl intro, we're talking a year. It probably won't be that long. ...but that's just the point. You never know. You just have to give it as much time as it takes!
Just make sure to give Dusty LOTS of extra attention. And I'd take Squeak into a room by herself for 20 minutes each morning and evening to give her a LOT of alone play time - and if you don't work and are home during the day, give her lots of interactive play time (making sure to give Dusty attention first) - and help work off some of that energy so it isn't all directed at Dusty.