C.O. :
You can't tweak the signal to remain in your house. What you can do is to restrict the computers which can attach to the base station by MAC address, i.e. to the unique addresses of the wireless cards in the laptops.
WEP is also worth turning on, even though it's weak and easy to crack. I'd concur with going with an Ethernet solution for the router, and if your printer has a network port it may be possible to attach it to the network and print directly to it - my wireless base station can turn itself into a printer server.