Your MacBook does not use iOS, which is used on iPhones and iPads. The operating system on your MacBook is OS X 10.5.8.
You probably want to upgrade the operating system to install iTunes 10.7? That requires OS X 10.6, and your MacBook needs a minimum of 1GB of memory. If it has 2GB already, you're all set there. And of course you'll need some free disk space in addition to whatever you have on the system today.
You can buy OS X 10.6 from the online Apple store, which in the US is at 800-MY-APPLE or online here.