I want to improve upon this deck: http://deckbox.org/sets/120332

With cards from my inventory: http://deckbox.org/sets/120323

Anyone got any ideas? :)

Under the assumption that this deck is meant to make the best use of Charmbreaker Devils and Burning Vengeance I would recommend the following.

Remove:
2 Fortress Crab
1 Into the Maw of Hell
1 Pitchburn Devils

Add:
2 Lightning Bolt
1 Sturmgeist (it looks like you have a second one available, if not you can use Flame Slash)
1 Fireball

Given that you don't have enough of the right cards here to play a really focused strategy I think your best odds are to use your burn and bounce spells to keep the battlefield clear. Then you can swing in with Murder of Crows, Sturmgeist, Scourge of Geier Reach and Charmbreaker Devils.