Help want to upgrade!

[msproject251]

My current specs:
i7 4790
gigabyte h81m-h one ram slot damaged(one of the lock on clips broke off)
16gb ram corsair lp
gtx 750
500w cheap Chinese psu
cit galaxy evo case
I really need to upgrade my pc, right now I can spend £150 so I might get rid of the case, motherboard and power supply since I'm going to upgrade to a gtx 1080/1070. What should I get?

 

[n0ns3ns3]

you should:
1. get a good PSU - 50-100 pounds
2. get a better case with decent airflow
here you are probably close to your current budget limit
you can:
1. if your CPU is i7-4790K then get a decent Z87 or Z97 based mobo to have an overcloking option - but really not must.

 

[msproject251]

you should:
1. get a good PSU - 50-100 pounds
2. get a better case with decent airflow
here you are probably close to your current budget limit
you can:
1. if your CPU is i7-4790K then get a decent Z87 or Z97 based mobo to have an overcloking option - but really not must.

I have a non-k version.

 

[n0ns3ns3]

then just the PSU and a case.
if you want recommendation I can have a look what will fit 100-150pounds