Corby's the guy to speak to about that, as he made the banner. However, it looks to me that on the banner there's some form of low opacity texture (it looks like flaking paint from where I'm sitting) added as a low opacity layer (possibly multiplied/overlayed as well).
Are you trying to achieve something like this?
To this, I searched on Google images for 'Wood Texture' (under Large Images Only). Copied and pasted a section of it on top of the image you posted, changed the blending mode to Overlay (you can use Multiply as well, but it'll appear much darker) and dropped the opacity down to about 70%
For a more abstract feel to the overlayed layer, you could try playing with Threshold as well, Image > Adjust > Threshold. I hope that helped. If you want any more help, let me know.
Here's the same image, but with Threshold applied to the overlayed layer, and the opacity down around the 20% mark...
Obviously, you'll get different effects from overlaying different textures. I pretty regularly scour Google images for different types of textures, and I have built up a pretty good library of stuff I've found, and stuff I've made and scanned in myself for use in images. Like this from my website, for example:
Sorry, I'm rambling now... :oops: