This can be done, but with not with equipment you can get off of best buy or walmart shelfs.
You would need to get routers with external antenna ports, and securely mount a yagi directional antenna on the roof of each house, and this is completely requiring that the antennas that they have line of sight to each other. In short, if you both cant stand on the roof of the houses and see each other with a good pair of binoculars then you do not have line of sight.
You will also need to configure the routers appropriately and possibly need to flash the routers with dd-wrt.
To do this right at all it is a $300-500 endeavor and requires someone with at least mid level computer abilities.
This is using home/small office grade equipment and not commercial grade (a single dual radio router can go for $500-2000 alone)
If this is something you want to pursue we can take it further, but anything less then this will be 15% functional to completely useless.