@lcsoloman1 Your graphics chip is actually a bit slower than the minimum requirement for the 64-bit version of Sims 3. That doesn't mean you can't play, as you've seen, just that there might be some compromises. For now, try enabling Advanced Rendering to see whether that makes a difference. Change the setting at the Main Menu, then quit to desktop before loading the game, or you might see some very strange graphics glitches.
If this doesn't help, please post a couple of screenshots showing the issue. If the in-game screen capture tool doesn't capture the mirroring, you can put the game in windowed mode (click cmd-return) and use cmd-shift-4 to capture the portion of screen you want. I'll try your graphics settings myself and see if I can reproduce the issue, although I have a different graphics card, so I may not see the same thing.