The CD broke!!!

I was installing my good old The Sims 2, I have them on CD's from way back when there was no other way to buy it... but as it was time to put CD3 in... it cracked... just as I was gonna take it out of the box... I tried skipping it and proceeded to installing the extansions, also from CD's, but they all need the base game apparently... I thought some bigger extensions won't need the base necessarily and can replace it? I guess that is not the case with Sims 2? What do I do now? Is there a way to install it without the CD, and without buying the game allover again? Help... I am so sad...