To charge your bank you can use one of the charger circuits that came with the disposable cameras (remember the one that you left a capacitor on?). Simply take two wires (use separate colours) and wrap the ends around the legs of the capacitors, then add some solder to the joints.
This will make for a basic charger, how ever, it will take quite a long time since it was only designed for use with one capacitor.
Put it back in its camera casing and run the wires so they come out of the case, you can snap a hole in the casing if needed. Use electrical tape to secure it all.
It is also a good idea to snap off the plastic around the battery area so you can easily remove the battery.