An Intel Core i3 CPU from Intel would also be a great choice, with lower power usage than the AMD CPUs.
The Intel Pentium CPUs would be OK for this specific game too, but the Core i3 will give you much better general performance.
A good graphics card for the price is a GTX 760, its $200 and completely worth it. You will run LoL at about 90FPS on Max. As well as other games, you will most of the time, be able to run it over 60 FPS on Medium or High settings. So yeah.... There is the 660 or 760. But I highly recommend the 760