Any of her pokemon you are stuck on particularly?
From what I see, she checks 4 of your mons easily, especially that Ampharos. (rip)
So let's see:
You can catch a Sealeo and evolve it to Walrein from the mountains connecting Calcenon & Ametrine (What I used and probably your best bet cuz of its nice stats)
Head back to Ametrine, you can catch a Snover or Abomasnow.
And if you surf on the water near Titania & Amaria's house you can probably find a Wailord or Wailmer iirc