PS3 issue

I am having trouble setting up audio to my monitor.I have my computer and my PS3 running to it.My Pc of course has sound but I dont have anyway to run sound unles I buy a Gateway speaker bar.Any other ways to do this would help.I took my PS3 from upstairs where i had it connected to a 42inch Toshiba.I have always saved all my cables and add on junk but I dont have anything that plugs into the monitor that will work.I even have an old set of DELL speakers and a set of insignia speakers but both have the same kind of connector. The thing on the monitor is called a power in jack.