Please help. Iphone 5 and itunes download.

Please help 😟

Today I bought the iphone 5. Tried to sync it to my itunes but had a message come up saying 'The phone Natalie's phone can not be used because it requires itunes 10.7 or later' I've followed the instructions and been to www.itunes.com/uk and clicked download on itunes. It seems to download, and a message comes up in norton saying itunes setup 12 exe (or something like that) It doesn't ask me to restart my computer or anything. I've tired a few times both restarting and not and when I plug my phone in, the same message pops up that I need to download 10.7 Please help, been trying for hours.

Thank you in advance for any support.

Natalie x