If I understand correctly, you have 2 machines:
1) a linux server running some hypervisor and libvirt.
2) a windows machine with win32 virsh
Now, you want, from the windows machine, control the hypervisor running on the linux machine.
If this is correct, the command in the windows machine should be:
virsh -c qemu+tcp://ip_address_of_the_linux_machine/system