Can't update to itunes 11.1.1?

My mac is quite old and i tried to update to the latest version of itunes because it wouldnt let me sync music to my iphone anymore, but it won't update either. How do i sync music to my phone now that itunes is discriminating against me?

I tune ins't discriminating it is telling you that you need to upgrade to a new or gently used newer Mac thats all. I'm not sure what Itune you have but here is how you sync your phone with the itune.
http://support.apple.com/.../kb/HT1386