Further, since you still have the threshold layer sitting in your layers palette we can select the image from that B&W layer and extract the black image leaving it by itself with a transparent background (hit Ctrl+J to do so). Ctrl+U will bring up your Hue/Saturation dialog and clicking on colorize we can now alter the color. First set the lightness to something like +10 so that you can see the changes while sliding the hue and saturation sliders.