I have the same trouble with this kitset - when it's dark the IR LEDs are active, which then only reflect in the glass and blind the camera. Going by what I could see in the image, my windows' glass is barely transparent in infrared anyway.
I suggest getting a separate compatible weatherproof camera and set it up outside. Going by the display in Jaycar Wellington, you can take your pick of the Signet range.
I'd be interested to hear if anyone has had luck with cameras without in-built IR LEDs at night through glass.
Hope this helps.