This quest will be unlocked if you talk to Damien after you have discovered the name of Clara's twin sister which is Britney. Damien will then asks you to go find Clara's real name by talking to his contact that will be able to pull some record about Britney.

Go to Dream City Public Library at South Metro area between 8 am to 4 pm to find Katherine. She's willing to search for Britney's record if you pay her $50. Wait for a day and then return to her. She will reveal lots of details about Clara and her real name which is Elizabeth. Go back to see Damien. He will then reward you with a diamond ring worth around $800 to $1000.

You can sell the ring to Pawn Shop at Old District for cash. Now you don't have to worry about money. At least, for now.