where can I get a version of itunes 12.3 that works with windows vista

I have recently updated my iPad air to IOS9.0.2.

I wanted to back-up my device using itunes but the current version (12.2.2 I think) saif that the iPad could not be used as it needs a newer version of itunes. I presume this is 12.3 - but the only downloads available seem to require windows 7.0 or higher. Where can I get a version of itunes that works with iOS9.0.2 and runs on vista?

Thanks

David