Rubies add a flat amount of damage to weapons.
So take the average damage of the weapon, add the bonus for whatever Ruby you're looking to compare it to (11 in this example), then multiply by the attacks per second. Voila! Now you can compare the two weapons equally!
((WeaponMin + Weapon Max) / 2) + RubyBonus = Average Damage
Average Damage * AttacksPerSecond = DPS
The math gets a great deal more calculated if your weapon has your class' primary stat on it. In that case, I'd suggest paying Covetous Shen - gold is easy to earn, after all.
