I will tell you one thing. You're not bad at all based on your scores per games, but Warwick is bad in bronze, trust me, i tried him.
Me, i go mundo only right now and since then, i win almost none stop. I go mundo top or jungle. Gang-Plank is also very good in bronze.
I would advise you to take a champ who has great mobility, tankyness and a champ who knows how to survive. You also need one that can deal damage to all enemy team at once. Since bronze players like to clump-up in mid a lot, you need a lot of AOE's. A lane pusher is gonna help you separate the enemy team and if they don't separate, this mean you get to pick an other free tower.
You must never die because if you do no one will be left. Bronze players die a lot. This mean, if you`re dead, it's an ACE.
Mundo is the best at all of this togheter. Gang Plank comes after him.
None of the champ you pick are good at this.
Cho-gath is acceptable: he can grow very big, he got stun, an instant big damage and a lot of AOE's. He is also good enough as a lane pusher. 1 problem, he got no mobility so if you don't have 6 stack, good luck.
If i were you, this is the list of champion i would go for:

