Old Soldier,
Here is another site you can look at for housing:
http://clasipar.paraguay.com/
According to statistics, internet penetration is only lie 12% or 15%. So to get the best deals on anything you will probably have to go and search in person, on the ground, walking. It will be great fun!
As for educating your son,.... a year in Paraguay will be more beneficial than any curriculum. At least that is my opinion.