For an easy $20,000, after your partner has the "package" with him, go in the house and head upstairs at the first staircase. Kill the guard with the garrote wire, then wait for the maid to leave the next room. You will hear a guard talk to her before she walks away. Kill that guard, but be careful -- make sure the maid does not see you. Follow the maid through the door on the right. When she is facing away from the guard, silently kill the guard. To the left (behind the maid) you will see the money bag containing the $20,000. Always crouch and use the garrote wire so you are silent and do not get caught.