Make sure that the printer is on and installed correctly and that the Desktop is on. Right-click on the printer and enable network sharing.
On your laptops, go to control panel and go through the "add printers" wizard. In the wizard, there is an option to install locally or through a network; select the network option and follow the prompts.
This works fine as long as the desktop is left on. The only way around having to leave the desktop on is to by a network adapter for your printer.