Could someone walk me through the process of how to download this pack, i've tried but the site keeps directing me towards purchasing the game for the PC first. I'm on PS3 btw.

Steam is for PC only. You have to activate the code on PSN for PS3.

Oh? So is it just through the redeem codes section of the playstation store I take it?

I would presume it's the redeem codes section for the PS store, as it was that for the Xborx ones.

This damn card I got for the download is extremely missleading then. I suppose it makes sense on how you'd then transfer the game but still, it takes people like me time to connect the dots lol

Why is it misleading?

What does it say exactly?

It tells me to go onto Steam online and enter the code in order to obtain the download but does not detail anything about the game's platform. Perhaps the clerk gave me a card for the PC version rather than the PS3, are there differant cards for each system?
The code is too long for the PSstore redemption panel which makes me think i've got the wrong card.

Yep, it sounds like the less than intelligent clerk gave you the wrong card.

PS3 card should make no mention of Steam. Suggest you take it back to the shop, explain that you purcahsed PS3 version (Show your receipt) and ask them to give you the correct one.