all three can use the wireless signal to connect to the internet
I assume you have a wireless router? and you are using DHCP? or are you using static ip addresses ?
the two you want in the netwok w/ the printer, give them the same workgroup name, for the time being turn off any firewalls. Create an account w/ a password on each machine, then switch machines and log on w/ the same account. You have to have both accounts on both machines ( no server). Then share your printer, in the share include both log on accounts , do the same for the "security" tab.
all three machines will be able to surf the net and two will be also networked...thats it.