You have no MobileMe files, I'm afraid; MobileMe closed last August and the entire contents of your account have been deleted and are not recoverable by any means.
You can reactivate the address (though not any previous emails) by going to System Preferences>iCloud and signing in there, and enabling Mail in the checklist. After all this time I'm not sure whether you will be able to retain the @me.com version of your address, or whether you will only be able to use the @icloud.com version, but you may be lucky.