I'm getting a Rx 470/570(Depending on my budget and the price). I got a Xeon E3 1220 CPU and i don't really think it's a very powerful cpu so I'm also thinking of upgrading it first. I'm just aiming for a 60 hz 1080p med-high settings experience so it's fine if it'll just bottleneck a little bit. So should i get the gpu or not?
Maybe, maybe not. Depends on the game, how much system RAM you have, etc.
The RX570 is good for medium settings at 1080p @ 60fps on average. Some games are more CPU intensive, some are more GPU intensive.
Throw the term "bottleneck" out of your vocabulary. When it comes to PCs, particularly "is this GPU good for this CPU" (or vice versa), it's been abused/misused to the point of uselessness.
Assuming you have a weak GPU now, it will definitely improve things.
If you're asking "can getting a better GPU (or CPU) while leaving everything else the same somehow hurt performance?" then the answer is a resounding "
NO" - you'd be surprised how many people think that can happen.
The one thing I'd be concerned about is your PSU. Can it handle the needs of the new GPU?