I can't download itunes 10.7 on macbook

I am running Mac OS X version 10.5.8 and am unable to update to the newest software because of my processor (2.16 GHz Intel Core 2 Duo). Perhaps I'm wrong but as far as I remember I was unable to update my software last time I tried. I now want to update my iTunes to the latest 10.7 version so that I can plug my iphone 4s running on the latest iphone 6 software into my computer. However, when I went to install itunes 10.7 i was informed it can not be installed on my Mac OS X. Is there a way around this problem or am I stuck with a computer that is not compatible with my iphone?