Camera technology and capabilities are going to many times, be directly related to their age. The CGO3 is currently 3 year old technology... there is little that can be done to improve the image quality, with the possible exception of changing out the OEM lens with a reputable 3rd party option.
If the CGO3 quality will not be enough, frankly you need to look at a newer drone/camera... the C23 on the H Plus has gotten quite a few positive reviews on this board. Or possibly a 920 / CGO4 camera... also a 3 year old platform, but the CGO4 is far superior to the CGO3.