on Oct 24, 2015 at 8:24:57 pm Last Edited By Kalle Kannisto on Oct 24, 2015 at 8:27:13 pm
You'll need the texture as a black and white image. The preferable image would be full range (black to white), as opposed to very light or very dark.
When you have the texture, you should be able to place it in front of you flat background color, behind the text and change the blending mode to overlay or soft light. May need to adjust the opacity as well.
There is another effect, a vignette (darkening toward the edges/corners) on the background as well, which you could either do directly on your background color as a radial gradient or on a separate layer as an overlay.
Do you mean the yellow extrusion/bevel on the lettering? Or the texture?
Lettering: Duplicate your text layer, fill and stroke it with yellow and offset to down and right. Change the stroke of the top copy to same color as the background and fill to light yellow.
Texture: Easier to do with Photoshop (if you have and know the program). You basically need the texture that ONLY has those small "grunge" details and is otherwise transparent. Then you can put it atop the image (either in Illustrator or in Photoshop) and lower opacity some.