No expert here, but in Photoshop (and I assume Fw would be similar) I would—
- double click the layer in the layers palette and rename it from Background to anything else
- select the magic wand tool, set a very low tolerance in the toolbar top left, click in the white area to select all white pixels, and press delete. That changes the white area to transparent.
- choose the black decorations with the same tool to select them all and then change their color
- create a layer below the decorations and apply a gradient to that.
A couple of far easier and non destructive method , since you are fortunate enough to have a grayscale pattern.
- Create a NEW shape layer that covers the whole canvas.
- In that layer go to Fx and make a gradient overlay to match the gradient in your desired image ( which seems like a basic linear gradient , so that should be a snap).
- If it wasn’t already, move the shape layer BELLOW the pattern layer
- Set the pattern layer blending mode to multiply.
You can even have COLOR versions of your patterns by employing this method.
- Copy your pattern into the clipboard.
- Create a shape layer, covering the whole canvas, of the desired color.
- Add a gradient mask to the shape layer
- Option click ONCE on the gradient map ( the canvas should turn white) , and PASTE your pattern ; it is now pasted onto the layer mask you just made
- Select ALL then , INVERT ( so that black turns to white and white to black)
- Create a new shape layer
- In that layer go to Fx and make a gradient overlay to match the gradient in your desired image.
Hope that helps