I got a monthly report dated 10-21-07 to 11-20-07, it is not 01-09-08 and it has yet to reset giving only Oct. - Nov. information. I do have the display monthly report box auto.... checked however i don't seem to be recieveing a new report.
What version of OneCare are you running? If you are still using the beta, 2.0.2394.2, you will need to uninstall it and reinstall from http://onecare.live.com.
If you are running version 1.6 or production version of 2.0, having updated from 1.6 already, I would recommend contacting support to have this investigated, because I would have expected several reports to have been generated and presented to you by now.