first: spay her. this will PROBABLY help to cut down on aggression issues with the new cat.
second: go younger. older cats seem to accept younger/smaller cats better.
third: i would wait until after the move, just because bringing home a new cat prior to a move is a LOT of change for that cat to handle, and you’ll want introductions to be slow (at least a couple weeks of no-contact aside from sniffing under a shut door).
in the interim, research methods of bringing a second cat into the home. there’s a lot of info out there, and doing it right can mean the difference between getting along and wanting to kill each other.
We would take our childhood parakeets to the Vet to have their nails trimmed. You may be able to find a veterinarian near you who will trim parakeet nails. They are so skilled they are usually able to do it quickly causing little stress. Good luck!
As this is your first time, I’d let the vet do it first and show you how he/she does it, so that you could do it at home next time. Good luck 🙂