Sue for back rent and unpaid utilities

I had a tenant who moved out because she could no longer pay the rent. However, she owes me $4000 in back rent and $700 in unpaid utilities. What is my best recourse to recover this money. I have no forwarding address, but have her place of employment.
Thank you

I forgot to mention that I am in GA. Also, is there a way for an individual to post a negative mark on there credit reports?

First send a statement of all monies she owes you to her, at her employer if necessary. Send it by certified mail, return receipt requested, and keep a copy. Mark the bill "Due immediately." If she fails to pay, sue the former tenant in small claims court for all monies she owes. Have her served at work if you cannot find her new address after a search. (You could always have someone wait outside her work and follow her home to find her new address.) You can also try several internet searches, including google, zabasearch, and others. Once you get the judgement aginst her, have the clerk record it. This will put it on her credit record. You can also file to garnish her wages for the judgement.

Thank you!!