Possibly, you could install boot camp on your Mac, (meaning that you would install Windows on that boot camp partition), install the boot camp support software on THAT Windows system.
Then, copy only the Boot Camp control panel to your PC. (should work... I think)
Another possibility - Install something else Apple that can be installed on Windows, such as iTunes, or iCloud. That may pull in an Apple support preferences panel, that may see and download whatever is needed for the trackpad, too. Be sure to leave the trackpad attached while you set up that kind of install, to make the process more likely to provide that trackpad support.