There will be the words 'Sync Phone' and you click on that. Your iPhone will ask you if you 'Trust this computer?' and you choose 'Trust'. When you get iTunes downloaded to your computer, open the program and then use a USB cable and connect your phone to your computer. You had to have used an ID when you set up your phone (also, if you have ever bought any kind of app for your iPhone, it will be the same password and email that you use for those purchases). It will ask for your iTunes password which is the same as you Apple ID.

Do this WITHOUT having your phone attached to your laptop.

It is obviously free of charge to download. You can do so by simply doing a search for 'iTunes Download for Windows 7' on whatever browser you use. However, you DO need to download iTunes to your computer. I can tell you that you can, indeed, sync your iPhone to your computer without the need to download any 'drivers' of any kind. I also have an iPhone 4s and am running Windows 7 on my laptop.