I have to agree with the others, I dont understand why you got a pup when you knew the other dog is aggressive.
Could you explain please?
I have a 13 year old schnauzer cross, we got our yorkie pup a few months back and at first Jess (cross) didnt accept Poppy (yorkie) at all.
She just wouldnt even sit in the same room as the pup.
I got Poppy at 6 weeks old, she is now 5 1/2 months old and Jess has only JUST started to accept her.
They now get along well but this dosnt mean that the same will happen to your two dogs.
Hopefully you can give us a little more information on the situation so we can help you better.