4th Gen Training my Pachirisu/party for the Water Gym

[martijn]

What Route would you guys recommend training my Pachirisu on?
I need to get it in shape for the Pastoria City's Water Gym.
Also I'm not sure about my party for this Gym, so I'm listing that one, too ;)

Pachirisu Lvl 24
Stats:

• HP: 68
• Attack: 33
• Defense: 46
• Sp.Atk: 27
• Sp.Def: 54
• Speed: 53

Attacks:

• Cut: PP 30
• Swift: PP 20
• Shock Wave: PP 20
• Spark: PP 20

Roselia Lvl 33
Stats:

• HP: 85
• Attack: 40
• Defense: 47
• Sp.Atk: 78
• Sp.Def: 66
• Speed: 58

Attacks:

• Mega Drain: PP 15
• Giga Drain: PP 10
• Toxic Spikes: PP 20
• Sweet Scent: PP 20

And my other party members include:

• Staravia Lvl 27
• Crobat Lvl 26
• Geodude Lvl 23
• Monferno Lvl 28 but I can get a Turtwig evolution of about the same level.

Any advice would be great! Thanks in advance!