Are my pokemon too weak to battle Clair in pokemon soulsilver?

From experience I'd say, definitely, my level 50 Typhlosion had one hell of a bad time, yeah I know it was at a disadvantage but it had Rock slide, get your Pokemon to around 40-45 and keep at least 2 Pokemon that has a move strong against her Pokemon, a good Pokemon would be one that has a Dragon type move, for example your Gyarados can learn Twister, Dragon Rage isn't a good one because it's limited to only 40 points of damage. Her team will fall to mostly Ice and Dragon type moves except for Kingdra which will only fall to Dragon type move, Rock type moves will work as well, hope this helps