Pokemon Soul Silver Team Help?

You can get the water stones at the pokeathalon on wednesdays for 2500 points it was the easiest way for me to get them. Dusk stones are more rare until you have gotton the national dex so the only way to get one is to come in first at the bug catching contests. Murkrow and bayleaf will be the most use full in this Gym battle though. The 5th gym leader has a level 29 primeape and a level 31 poliwrath. So I would use murkrows wing attack on pimeape and any gr attack on poliwrath should end the battle pretty easily.