Advice on upgrading old Dell XPS gen 5

[themadhatterm983]

hey there

I'm looking to upgrade my ancient Dell XPS gen 5

Current Specs
Intel pentium 4 640 3.2ghz with HT
4 GB (2x2GB) DDR2 ram
Nvidia 6800
460w dell psu
and all on the dell motherboard

I want to upgrade to
AMD FX 6300
Gigabyte 970A UD3P motherboard
Some cheap DDR3 ram (probably CCL choice and 4GB of it)
And a AMD R9 270

my questions are

1. Would this be a good build being able to play latest games at 1920x1080
2. What should i upgrade first CPU,RAM and motherboard or GPU
3. Any suggestions to make this a better build?

Also i am in the UK

 

[Kisianik]

You have an old PC case with proprietary PSU, so you simply need to build new PC - with new case and PSU.

Use GEN5 as secondary PC.

 

[themadhatterm983]

You have an old PC case with proprietary PSU, so you simply need to build new PC - with new case and PSU.

Use GEN5 as secondary PC.

problem with that is I don't have the funds to build a whole new system
i got given this one and was hoping to use as much of it as possible
any other suggestions??