Sisters of battle

I have been having a problem with making my SOB army competitive enough. so this is what I have come up with for a trial list to play. Does anyone think of anything that is a must have for SOB army? I would like to put a squad of retributers in but I am short on the hvy bolters. I figured I would need 3 SOB troops as they just plain suck, 1 to sit on an objective and then two more to go get an objective. and being SOB I needed assaulting units.....very limiting.

Sisters of Battle Roster

1 Saint Celestine, 115 pts

1 Uriah Jacobus, Protector of the Faith, 90 pts
1 Battle Conclave, 170 pts
1 Crusader
4 Death Cult Assassin
1 Immolator (Extra Armor; Twin-Linked Multi-melta)

9 Battle Sister Squad, 190 pts (Flamer x1; Meltagun x1)
1 Sister Superior (Melta Bombs; Power Sword x1)
1 Rhino (Access Points: 3; Fire Points: 1; Storm Bolter)

9 Battle Sister Squad, 190 pts (Flamer x1; Meltagun x1)
1 Sister Superior (Melta Bombs; Power Sword x1)
1 Rhino (Access Points: 3; Fire Points: 1; Storm Bolter)

9 Battle Sister Squad, 220 pts (Flamer x1; Heavy Flamer)
1 Sister Superior (Melta Bombs; Power Sword x1)
1 Rhino (Access Points: 3; Fire Points: 1; Storm Bolter; Hunter-killer Missile; Storm Bolter)

9 Dominion Squad, 235 pts (Flamer x2; Meltagun x2)
1 Dominion Superior (Melta Bombs; Chainsword x1; Plasma Pistol x1)
1 Repressor (IA) (Dozer Blade; Searchlight; Smoke Launchers; Pintle-mounted Heavy Flamer; Storm Bolter)

1 Exorcist, 145 pts (Storm Bolter)

1 Exorcist, 145 pts (Storm Bolter)

Validation Report:
d-1. Formatting: Competition Output; c-1. File Version: 1.43 For Bug Reports/www.ab40k.org; b-1. Roster Options: Generic Unit, Imperial Armour, Special Characters; a-1. Scenario: Normal Mission
Roster satisfies all enforced validation rules

Composition Report:
HQ: 2 (1 - 2)
Elite: 0 (0 - 3)
Troops: 3 (2 - 6)
Fast: 1 (0 - 3)
Heavy: 2 (0 - 3)

Total Roster Cost: 1500