What levels are your Pokémon currently? If you've just started it might be too early to use a Pokémon that is caught at level 41-44, and you could catch one yourself during the day once you've finished the game.
I think a better idea would be to catch yourself a Rockruff, then when it reaches level 24 trade it to a Sun user such as myself so they can evolve it for you into the form that you want.