here ya go
I've not used fireworks, but in photoshop, I did a select->color range and tweaked for the blue. I used the polygonal lasso to clean up the selection. I defined the pattern, did a fill->from pattern. I then selected the small faded portion and did a hue/saturation->colorize to get rid of the blue hue that remained from the partial transparency. To obtain the hue, I used the eyedropper on a lighter box of the pattern.
The biggest problem here is that the pattern you provided was not correctly matched, and would generate a secondary pattern when tiled.
I took the initial pattern, and rotated and cropped it so that it would align somewhat properly. To correct for density variations, I made a duplicate layer at 50% opacity and flipped horizontally. I repeated this process vertically.
Because the pattern could not be easily cropped in such a way that it would tile without creating a secondary pattern, I made several duplicate layers, expanded the canvas size, and manually lined up the layers to create a larger swatch without secondary patterning. The file I created was then used to set the pattern used above. I've uploaded the
pattern so that you can continue to play with it if you like. I did not check the edges to see if they would tile, so if you have a larger space to fill, you may need to repeat some of the above steps until you have a suitable sized swatch.