What are the pokemon you're using adn what are their moves and levels?

Also, it takes a long time to get eevee to evolve into Espeon or Umbreon cos it has to
have max happiness

You dont know how to train pokemon.Just teach grotle bite and train in the grass to pwn
her pokemon.

Corrections:a dusk stone doest work on eevee,there is not a thunder type only electric
type,grotle can learn bite also,trading grotle for an extremely powerful pokemon is dumb
because it wont listen to you and nobody would want your grotle.

Go to the Abandoned Mansion (by Eterna City), catch a Ghastly, and evolve it into Haunter.
Ghost is super effective against itself. But, teach it strong moves because one of
Fantina's Pokemon are bound to know a Psychic attack, and that's not fun for your
Ghost/Poison type (Haunter).

Here's a page for Ghastly:
http://www.serebii.net/pokedex-dp/092.shtml

Here's a page for Haunter:
http://www.serebii.net/pokedex-dp/093.shtml

If you want, when ever you're ready, we can do a trade to evolve your Haunter into a
Gengar.