I'd say do CPU first. 4C/4T simply no longer cuts it. You can't go wrong with an R5 3600, or even a 1600/2600, and that shouldn't even be that expensive. Get a $100ish good quality B450 motherboard and 16GB of RAM. That should set you back $300ish dollars, which leaves with you $200 for a graphics card. I'd recommend saving an additional $100 or so and get the RX 5600XT or the 5700, because the $200 cards despite being an upgrade to yours, aren't really that big of an upgrade.