Maybe you can try setting a scheduled task that runs hourly (or cron job on *nix) that runs a script equivalent to
w32tm /resync
Kind of odd that you're getting that much drift though - I'd be trying to pinpoint the cause of that as well if I were you. I've seen this happen before with a piece of software (it was antivirus software when I saw it) causing the clock to drift until the scan engine was updated.