Haven't played it in like a year, so I'll try to do my best. Go in the direction of Cherry Popper's from Diaz's mansion, and when you get off the bridge, take a right. Go straight until you get to another bride, and head onto it, and it'll take you to a little island. It's somewhere there.

If i'm completely off, I apologize. Once again, I haven't played it in almost a year.