Start by opening one of the pictures you took. You might want to use the "Rectangular Marquee Tool" to at least crop out anything on the sides of the picture that you do not want. Just take the "Rectangular Marquee Tool" and click and drag a box around the area in the picture you want to keep and choose, "Image --> Crop". This will get rid of any "extra" stuff on the sides you do not want.
Step one is to take the original background and duplicate it by dragging into onto the "New Layer" icon located on the bottom of the layers palette. You should now have two layers. One named Background and one named Background Copy.
With the layer Background Copy selected, choose, "Images --> Adjustment --> Desaturate". This should make the Background Copy layer black and White.
Now, go up to the Menu Bar and choose, "Layer --> Adjustment Layer --> Hue/Saturation...". Just OK on the dialog box that opens. This will being up a dialog box like the one below. Make sure "Colorize" is checked and you set the values to match the box below. When you are finished, you should have a picture that looks like the one on the bottom. You are now finished!