Pokemon Platinum:How Do i Beat The Elite 4?

My Team Is: Infernape Lvl 71, Garchomp Lvl 48, Rampardos Lvl 37, Giratina Lvl 57, Luxray Lvl 41, Roselia Lvl 43. Infernape:Rock Climb, Rock Smash, Flare Blitz Flamethrower, Garchomp:Dragon Rage, Dragon Claw, Crunch, Dig. Rampardos:Endeavor, urance, Zen Head, Ancient Power. Giratina:Earthquake, Ancient Power, Dragon Claw, Shadow Force. Luxray:Thunder Fang, Flash, Spark, Strength. Roselia:Aromatherapy, Ingrain, Toxic, Petal Dance. PLZ HELP.