Gardevoir might not be that useful against the Dragon type tho (Poison/Dragon, a Sludge Bomb/Wave is more effective than a Dazzling Gleam, but a Psychic is just as effective as a Sludge Bomb/Wave though...)
The biggest threat right now is Muk (If she still has it...) Because of the bugged status (Mud Bomb reducing your accuracy by -2 instead of -1)... But honestly, a ground type can pretty much destroy everything... At least for me, Quagsire was a boss in my battle against Aya...
Nidoking/Queen is probably one of your best bets for now... But you should consider a Crobat also: It's goign to outspeed everything she has, meaning you can confuse ray everything she uses...
Also, i don't mean to ask, but: Do you have a Gyarados? I know i always talk about Gyarados, but really: The only moment she was useless in my playthrough was in the first gym... cuz she was a Magikarp...
Other than that, i can only say: Good luck ^^