i think the most official answer is to check the Sim3's website against your computer... and will see for sure.
but Dell 1525 is quite new, and that most games nowadays actually has a mode for computer with a less powerful graphics card, so the guess is that it probably will run.
Sims3 is much more demanding than sims2 & even knowing your build, one thing i can safely say is that your graphics, intel gma x3100 is outright crap
so even with most settings turned down, it's going to be pretty painful
Anyways, you can test your system for self
& yeah just to tell you, laptop graphics are non-upgradeable