To determine your Paladin's maximum damage you must multiply your weapon's attack by 8.1 and then your Distance Skill, then divide everything by 100.
For this example we will use Bolts that have 30 attack and the Distance Skill is 70.
So 8.1 * 30 * 70/100 = 170.1, so your paladin's damage will be 0-170, of course the damage will be reduced by the monster's defense. If you attack a player your damage will be half that, then it will be a maximum of 85, and will still be reduced by the player's armor (Shielding does not count).
In this case your crossbow's attack would add up to the bolt's attack. And the Hit% increases your chances of hitting the target.