I want to maximize my damage output on my character by Finding a way to add his Unarmed Strike Damage to his Natural Attacks.
If there are ways to do this I would also Like to know at what levels it would be available.
While it doesn't mix the damage, Superior Unarmed Strike is a Feat which sets the damage of your Unarmed Strike to a value much higher than it would otherwise be {barring levels in Monk or similar.}
A Necklace of Natural Attacks {Savage Species} with the Adaptive weapon attribute allows the wearer to apply the benefits of feats that affect other weapons to the weapon in question. This allows a character with both the Superior Unarmed Strike Feat and an Adaptive Necklace of Natural Attacks to replace their Natural Weapon damage with the damage for the level listed in the feat.
The downside? Having it affect more than one natural weapon increases the cost per additional Natural Weapon. +75% for the first additional natural weapon and +50% for each thereafter.
You can use the Beast Strike feat (Dragon Magazine 355) to add "your claw or slam damage" to the damage you deal with your Unarmed Strikes or to the damage you deal in a grapple (the "damage your opponent" option, I presume).
You may find the Black Blood Cultist prestige class (Champions of Ruin) interesting. Its 8th level ability allows you to deal the damage of all your natural weapons whenever you succeed on a grapple check. The class has a handbook.
Also, this question may be of use to you, especially the part of @KRyan's answer that has to do with combining natural attacks and Flurry of Blows into the same full attack routine.
I do not think that a way to add your unarmed strike damage to the damage of your other natural weapons exists.