Matthew 15.... my question is this, If he was only sent to the lost of the house of Israel...

It was not yet time for the Gentile,not untill after the resurrection.Did you notice here that Christ walked 50 miles one way just to see this woman,and turned around and walked back to where He came from.He was teaching the disciples,Peter was having a hard time understanding the parable of the sower.This was to help the disciples to understand.