Last I checked intel's chips (specifically the i3 and i5 lines) are plenty good for a normal person while not producing as much heat as AMD's chips, which is why the majority of laptops use them (as laptops tend to have heat issues).
While integrated graphics are crap in general, one on a new laptop with an i3/i5 would be good enough for the sims 3, so any i3/i5 laptop should play it fine.
If she wants to move up to other games in the future that might be a cause for concern, since you can't upgrade the graphics in a laptop like you can in a desktop,