Are you connecting the USB Printer to the Virtual Machine? (Sounds like you are.)
Connect it to one or the other and then either share it so the other can access it or if connect to the Host then the Guest should be able to print to it to using ThinPrint, a part of VMware Tools, which should automatically set it up in Windows providing you have the Virtual Machines Setting set correctly.
Have a look at the following VMware Knowledge Base Articles:
Printing from within a virtual machine in VMware Fusion