The AMD A10 is going to limit performance in games that require decent CPU power. This is going to be a problem in quite a few games.
Unfortunately there really isn't a worthwhile processor upgrade that will work with your current motherboard. It's a dead platform.
If you want to avoid bottlenecking a 1070 I would recommend upgrading to an i5-6500 and a H110 motherboard. You will also need at least 8GB of DDR4 RAM since DDR3 isn't compatible with the new Intel CPUs.
If this puts you over your budget I still think you would be better off with a new i5-6500 paired with a 1060 than you would with a 1070 paired with your current AMD A10.