You can just buy a connector at radio shack. Try not to cannibalize the "wall wart" (I call them transformers), and instead just buy the stupid connectors somewhere. I don't know why anyone would ruin the transformer when the connectors are available everywhere.
here is one type available at Radio Shack or any retail electronics store. They have different sizes too.
http://www.radioshack.com/product/in...ductId=2102487