I would second ebay, just purchased one, about £20 cheaper than Acer when the postage is included, and is identical to the origional, all the adapters are made by third parties as far as i am aware, put the third party manufacture in ebay or the model number.
I have repaired a split before too, chop the wire, strip the ends on either side, solder each the wires back to each other, and then put some tape over the join, works fine for me, and i only did it as the split was after the power pack, if its in the main power lead to the power pack from the wall it might just be a standard figure of either lead or that other one with three pins....