-- send Joey into her apartment to talk to her. After they say everything, notice that there's a note on the floor. It's in the dark, but that's easily fixed; just have Joey blow it over to the door so he can read it.
Hint 3
It says "I know about Heather. J." Tanya denies any knowledge about any of this, but that doesn't mean there's no connection.
Hint 4
After you read the note and talk to Tanya about that and everything else, have Rosa search for the name "Tanya Corsey." (If you try and Rosa says she's getting ahead of herself, it means you're trying this too early. Read the note and talk to Tanya about everything, including Channel 11, then try again.)
Hint 5
Searching for her name gives you Channel 11 on the map. Go there.