Allright, i did not know that sensor size is more important than MP's :-(Another problem you have is that the sensor size is too small for "good" night time performance at 8MP. A 1/2.5" sensor can provide a reasonable picture at night in a 2MP camera, but when going to 8MP the light is cut to, roughly, less than 25% of what reaches each pixel in a 2MP camera.
What replacement do you suggest with same type of camera?