all you need is 4 beefy diodes in a square shape to take the sine wave from AC and chop it up into a negative and a positive (DC)
if you've never seen that i'll draw you a picture.
i'm not sure what the output of a wall socket is, but shouldn't it multiply the amperage by 4 in the transformer because we are taking the voltage down so much?
i would just try a 4:1 transformer followed by a normal DC rectifier (its even easier to just buy one of these instead of doing the 4 diode thing, they sell them already together in a nice little ceramic cube
)