Looks easy enough to upgrade. What card you get really depends on what you're trying to do, but I don't see why you couldn't install a 1060, 1070, or 1080 card. I game on a 3770 processor (should be same as yours from what I can tell) and use a nVidia GTX 980 in 1080p resolution at 90-120fps for AAA titles.
GPU Upgrade is on page 31:
https://download.lenovo.com/consumer/desktop_pub/ideacentre_k430k410_hmm_20120627.pdf
You might want to measure the space for the card length to make sure extra long cards will fit, but I'd be surprised if they didn't. I don't see case dimensions listed in the in the docs.