... I'm not sure why the dog would move to I-12, but ok.
Spiked Gauntlet AoO - (1d20+2)[16] damage - (1d3)[3]
Twang - Round 10
5-ft step back to G-13
Move: Reload Crossbow (normal)
Free: Law-> Attack
Standard Shoot Dog.
Attack - (1d20+12)[26] Damage - (1d6+3)[5] (does the dog still stand?)
Free: Law -> AC.
Done
Stats
Spoiler
Show
HP: 9/9
AC: 25 (+1 size +2 armor +6 dex +1 shield +2 deflection +3 Law Devotion)
FF: 15, Touch 19
Shield of Faith: 1/10
Law Devotion: 2/10
Ammunition: 34 normal, 2 MW
Crossbow:Unloaded