You might try www.mpja.com and www.allelectronics.com. They have a whole big section of all types of power supplies. But jut FYI you dont need a 15v that can only put out a max of 467mA...it just has to be above that...like say if you found one that was 15 volts at 5000mA(5 A) that would be perfectly fine to use. What ever is drawing the current is only going to use as much as it needs and no more. (unless theres a short or something...which is why its a good idea to use a fuse...)
Hope that helps some.