How do make my Pokemon team better? Soul silver.?

So I just captured Lugia and am going to head of for Pokemon league and want advice. My pokemon, (type, level and moves) are below.

I have Typhlosion-56 (Bast Burb, Cut, Flamethrower, Lava Plume)

Onix-25, traded (Rock smash, Dig, Slam, Sandstorm)

Togepi-30 (Yawn, Encore, Sleep Talk, Wish)

Gyrodo-32 (Ice Fang, Dragon Pulse, Surf, Whirlpool) and

Lugia-45 (Extrasensory, Fly, Hydro Pump, Aeroblast)

So 1. What Pokemon would you reccomend as the 6th member/would you switch any of my members with other Pokemon? Where would I find these?

2. Are my moves good for these types of pokemon or do you have any recommendations for better moves and where I could find them?

3. I would like to add a dragon type to my team if to think that is a good idea. Where can I find these and what should I look for?

Thanks so much! Just whatever information you can give me would be very appreciated :)