Need help setting up ps4 to surround sound.

[TyGreen]

Hello, so up until I moved to ps4 I had to problem connecting my 360 to my surround . I just went hdmi to tv for picture and the RCA cables to my surround. But ps4 doesn't come with the av cable jacks. I have an older don't system that has one hdmi out then video out and audio (red/white) in. But no optical cord. And my tv has hdmi dvi in, and two sets of audio and one is in. The people at best buy suggested I but a hdmi to av convertor. Sorry for rambling on there but to my question, would I need that convertor and if so which way would I set it up. Or is there another possible way to get sound through my surround but still have hdmi picture quality