z0z55 Do the settings show as the lowest options on the Graphics Settings page? Or do they show as whatever you chose, but the game still looks to be low quality? Have you checked the Advanced Rendering box on the same page? Not doing so makes the game look low-quality at any settings.
Whenever you change any graphics settings, it's best to do so at the Main Menu and then quit to desktop before loading a save. If you didn't do this before, that might explain what you're seeing.
If the above doesn't help, please delete Options.ini, in Documents > Electronic Arts > The Sims 3, and load the game again. This will reset all the graphics options. Change what you want at the Main Menu, quit to desktop, reload the game, and see how it looks AND whether the settings you've chosen stuck.