I dont think there is a simple solution for your needs without overstepping
your budget.
If you could live wired rather than wifi you can get ccd/cctv color cam
that will do lower light levels for reasonable dollars. Network server for
cctv seem to start around $250 and upwards so maybe simply use a converter
to feed a capture device, make yourself a web page to view it - you'll
need to leave home computer running to use it.
fwiw;
Compex,
www.cpx.com makes a wifi router, np26g-usb, that converts to a
stand alone wireless usb webcam server. It;s based on a particular popular
camera driver so you might want to download its firmware and look at the
known camera's it supports. Think I paid $75 for that router online. You
could possibly add a $50 webcam and there you go, almost - low light.