To the OP-
I have about 150 hours in two O-470 powered 182s. Never liked them because they are air-trucks, not airplanes. They do one thing really well, haul a respectable load off a short runway and climb pretty good. I only flew them because they were available all the time in the club I used to rent from and faster than the Warriors and Skyhawks. No way they would cruise at 145kts. I think the upgraded modern ones can do that though.
The things you need to ask yourself are, will there be any more children and how much stuff does your wife and child need to travel with. The number one thing that makes Mooney owners switch to another brand is the need for more space and more useful load. I have never seen a Mooney owner switch to a 182. They usually go either to a twin engine plane, or the Beechcraft Bonanza. If you feel you need the space, I would skip shopping the 182 and look at Bonanzas unless you plan to operate out of short strips.
If you think you can pack light and you are done with expanding your family, the M20J is a great choice. You will save money operating it over a Bonanza and it will be much faster than the 182. Best to have your wife check out a Mooney first before you go to far.