All depends on if you are willing to spend any money or not. You have 3 choices.
1. Printer has to be on and connected to a pc that always has to be on in order for other pc's to print to it. You will need to make sure printer and file sharing is turned on. Sometimes sharing a printer on windows 7 can be a pain.
2. Buy the usb print server and hope that it works so that no pc's have to be on all the time.
3. Buy a new network printer(wireless or ethernet capable) and hook it up to your router