Play an all-offensive army. For this, drop the shooty squads as 2 shooty squads will hardly take down the tank you wish in the first two rounds.
Add a large crusader squad w/ power fist, melta led by the Castellan. These squads are really scary.
Drop the Castellan's plasma pistol as it can hurt your precious leader and will be shot at most one.
Drop the Command squad as it's too small or unify it with the Sword Brethrens.
Give it a Rhino with 10 members, one should have a power fist, another a melta.
I'm not a fan of unifying BT and GK as BT doesn't need any help from the Ordo Malleus.
I suggest dropping the GK's and taking Assault Termies and one or two Pred Annihilators for fire support.