HELP

i accidentally reformatted my ipod classic now it is being recognized as an external disc (this was done on windows 7) now when i plug it into to mac it only comes up as an external disc and doesn't show up on i tunes. on the windows computer, i cannot restore simply because of the ios error 1413 due to my daughters i touch. the i pod classic is now functioning as a external drive but i want it back as an ipod....please help!