Connecting astro a40 headset to pc with no optical port

[AyDreams]

I just purchased the Astro a40 headset because I've heard nothing but good reviews about it. (I believe it is the 2013 version with a mix amp included). The main thing I was looking for was surround sound. The problem I am having is that I don't have an optical port on my PC build. Now, I don't really know much about this but from what I've read, you need to have that for surround sound. I'm looking for any help I can get in order to receive the full potential of the headset. Is there a way to buy an adapter that will give me an optical port? Or really anything I can do here?

Here's my PC build (I can provide additional info upon request). :
CPU: Intel Core i5-4430 3.0GHz Quad-Core
Motherboard: MSI H81M-P33 Micro ATX LGA1150
Video card: Sapphire Radeon R9 280 3GB Dual-X
Operating System: Microsoft Windows 8.1 (OEM) (64-bit)

 

[Paul NZ]

You'll have to get a soundcard I would say with an optical port on it

Ive got a pretty old one here, dont know if it's still going. But its got optical in and out and spdif in / out connections