Sims 3 Custom Content?

I downloaded The Sims 3 from TPB, about a year ago. Since it's a downloaded copy of the game, I can't install .sims3pack files with the laucher, because it asks me to update the game. Is there any other way I can install custom content on my copy of the game?

I would get a legit copy and stop being a pirate if I had money to spend, but I don't. Ever thought about that? So either give me a useful answer or don't answer at all.