depending on your budget, you could either get the:
Intel® Core™ i3-4150 for 100 euros
Intel® Core™ i5-4460 for 175 euros
Intel® Core™ i5-4670K for a little over 200 euros (the K version isn't needed for you, since your motherboard won't be able to overclock, so you could get the normal version for about 15 euros less
hope this helps