Hey guys, just need some advice on a few upgrades on my PC, primarily looking at upgrading my mobo/cpu and a new case

Current specs:

CPU: i5 2500k 2012
GPU AMD 4gb 290x
Ram: 8gb ddr3 1333mhz
MOBO: P8Z77-V PRO (LGA1155)
Storage: 128GB SSD/2x 1TB HDD
PSU: 750w thermaltake gold standard

I got given 16gb ddr4 ram sticks recently but they are not currently compatible with my mobo – also wanting to look at water cooling for my GPU as well.

I also have Corsair Hydro Series H55 120mm Liquid CPU Cooler and was wondering if it would be generally compatible with new a cpu?

Price range

(This is in AUD btw, not USD)
CPU ~$400
Mobo ~$150

Thanks.

Honestly save money or get a better gpu.

You won't get huge gains upping cpu/mobo/ram. Mild oc and a new gpu would do you better.
Sell that ram and get more ram u can use and wait a bit to do a real upgrade.

This

I went from that exact gpu to a 1070 and its crazy the difference, even with my dated processor