Anyone have any idea if the components on the power supply board can be replaced or where to begin? It's really hard to see which components that needs to be replaced.. Maybe buy a new power supply from NewIt?
First of all, you should keep in mind is that capacitors in power supplies can remain charged even when disconnected, so you should exercise extra care and measure everything before touching it. Or risk getting a pretty nasty, possibly dangerous, shock. Which you don't want to do.
Assuming that you are knowledgeable and confident enough to avoid such danger, and that you are feeling adventurous, you could atempt to fix the power supply.
Electrolytic capacitors usually have an "artificial weak point", so to say, at the top. When they overheat, the weak point fails and the liquid exits from there. This helps avoid an explosion.
If you look at your picture, you will see a sort of inverted "Y" at the top (actually the side, as it is placed) of the capacitor at the middle of the board. This is the weak point of this capacitor. It is intact, therefore this capacitor is OK. Equally intact seems to be the capacitor at the bottom of the picture.
There seems, however, to be a blown-up capacitor at the top left of the PCB. It would seem that this is the part that needs to be changed. In principle, you could remove it and replace it with another one of similar specs (preferably one withstanding a higher voltage).
This assumes, of course, that the primary damage (assuming it is a blown capacitor) hasn't caused other components to fail too.
Whatever you do (find an adequate replacement power supply or fix the one at hand), you should also get a powered hub and an external PS for the arduino.