Late at party but u can do it anyway for the next Gym
Level Up Frogadier to Evolve and use Common Candies for the Level Cap
Use a Ability Capsule for Protean Ability (if u don't already have it)
Hariyama/Mankey is a good choise too but u beat her already, Toxic Spikes Trubish is good for the next Gym too (really helped me)
Got some pokes like Numel, Magnemite, Swinub, Littleo, Cubchoo, Bunnelby they are good for some Gyms later