Welcome to the sevenforums boland
There are in fact ways to force enable Aero on none supported graphics cards, but I've never had any luck with this working on older graphics cards.
Plus, if done inproperly can cause a lot of strain on your GPU and cause harm.
I wouldn't recommend it, but it is possible.
I'll provide the steps, if you choose you'd like to try it.
But I would highly recommend just purchasing a new graphics card.
You can get one that will support Aero for fairly cheap.