The 6100 will be a huge upgrade, your current one is rather meh. I suggest getting a 6300 over a 6100 though.
I am seriously considering upgrading from my Phenom ii 4 965 to a FX 6350 (just for ENB maxed out Skyrim!) but am super worried I will spend 130€ for no improvement, are you sure it's a big upgrade? What kind of improvement will I see?