Well thank god for that insight, DestroyerHive...
Anyway, that's a pretty tall order, Jason.
A lot depends upon what models you have available.
However, learn to love the Heavy Flamer. Sisters of Battle can carry a Heavy Flamer in basic troop units and it is astonishingly good against, infantry. It will certainly hurt 'nids, Guard and Eldar.
Use Divine Guidance for extra fun.
The Exorcist is perhaps the best tank in the game, if you can ever get it to work. Conventional wisdom is to take two, this I fully support.
Do not bother with the 'freakshow' units (Repentia, Arco-flagelants, Penitent Engines).
Be careful about how many =][= units you have in your army - some of them can be useful, but they are not faithful, and Faith is where your army lives or dies.
Consider something like this:
Canonness (Cloak of St. Aspira, Mantle of Ophelia)
Armed with either a blessed weapon or eviscerator and some kind of pistol, depending on what you feel like.
Either give her a jump pack or a Celestian Retinue and Immolator.
3-4 squads of Battle sisters
VSS (Book of St. Lucius, combi-flamer OR combi-melta AND meltabombs)
9 Battle sisters (Meltagun, Heavy Flamer)
Rhino
2 Exorcists (Extra Armour)
Add Seraphim or =][= to taste.