I think you should consider replacing Vileplume with Breloom. You could catch one at Friend Safari. As far as its moveset goes, try Low Sweep, Mach Punch, Bullet Seed, and either Spore or Stone Edge. For EVs, go with 252 Attack, 4 HP, and put all the rest on Speed. Its item would depend on its last move. If you go with Spore, then you should make it hold Life Orb. If Stone Edge, then it'd be wise to use Choice Band. :] Hope this helps!