The Turtlez is in the Turtlez Encampment you are given the coordinates to the encampment fairly early. It's in the first port town to strata, I forgot the name. Oul Rayle or something, you save a turtlez kid.
Just randomly scan in the shuttle in (I think) Northeastern Windor. That's how I found Turtlez HQ. Had completely forgotten the coordinates I got earlier.
But yeah, if you've already talked to Victoria, go to Turtlez HQ and talk to the guy immediately to the right of the entrance. He'll sell it to you for 120,000 gald. Then you have to talk to Duke Dalen in Barona castle and get another item from the final adult arc dungeon, then talk to the overseer, and finally you get Excalibur. (You also get Asbel's third mystic arte title along the way.)