LuckyGirl. Just because Microsoft continue to develop their product does not mean that the old one will stop working, even after they have stopped updating it. I am still using Windows XP on my server and that has not been supported for 2 years now, still works as well as it ever did.
If you are using Windows 7, your PC must be quite old, just stay as you are until you decide to replace it. Windows 7 will be supported until 2020.
Microsoft supports its products for at least 10 years, very few computers would last that long. So they haven't got you by the S&C's. In fact it is often other manufacturers that stop supporting their products first.