The one I posted is 500×234 and the one youre using is 214x100. Not sure why its so small, but you should use the link I posted instead of uploading it.

In the signature box, put [*img]http://img684.imageshack.us/img684/2441/sigpic2166918.jpg[/*img] (take out the * symbol) and your sig should be back to normal size.