on psypoke's attack list it states hidden power as being a normal attack but lets say you have a hidden power grass or any other special attack does it feed off your special attack or your attack since the attack is listed as a normal attack.

Special Attack if the type is Grass, Water, Electric, Fire, Psychic, Dragon, Ice, or Dark.

Attack if the type is Fighting, Flying, Rock, Ground, Ghost, Poison, Bug, or Steel.

then i just treat it as it's own attack and type. Also can you recieve stab from hidden power?

yes, but usually you have a stronger attack anyway if you want STAB. Also, getting a Hidden Power of a specific type is quite difficult in-game.