TouchCopy for PC will be able to detect your iPod Touch and iPhone that have been previosly been synced to a Mac and transfer all your content to your PC hard drive, or directly to iTunes on your PC.
Are you using a standard, click-wheel iPod?
In this case, Windows cannot read the Mac file system format on these devices natively. When iTunes in Windows asks you to restore the iPod - it wants to format it using the PC file system format, at which point you'll lose your music.
If you still have access to a Mac, please follow the steps below to transfer your music from a Mac formated iPod to a PC:
Such convoluted steps are not necessary if you're trying to use a PC formated iPod on a Mac, as a Mac can read Windows PC formatted disk drives and so will work with either PC or Mac formatted iPods. Therefore, TouchCopy for Mac will work with either Mac or PC based iPods when running on a Mac.