HP Slimline upgrade - feedback/advice please

[A47]

Hey guys, I have a HP s5615uk-m and planning to do some upgrades. I'm new to PC customisation so did a bit of research and realised I have limited options with it being low profile and all.
But here is what i'm planning to do.
Upgrading the PSU from 220W to a 400W TFX
http://www.amazon.co.uk/EZCool-Power-Supply-Small-Factor/dp/B0056G8L4K/ref=pd_sim_sbs_computers_1
And adding a LP 1GB GDDR5 Sapphire HD 6670
http://www.amazon.co.uk/Sapphire-11192-18-20G-HD6670-Profile-Graphics/dp/B0062CHLYI/ref=sr_1_1?s=computers&ie=UTF8&qid=1346343727&sr=1-1

What concerns me is:
- Is this the best choice for GPU
- Will the overall changes work out
- Do i need to add anything

The purpose is run not too demanding games like Guild Wars 2 on High settings, anything above 30 FPS is fine.

 

[Dark Lord of Tech]

No, both good choices.I run that card in my hp 6005 pro with the 220 psu.

 

[Saga Lout]

Hello and welcome to Tom's Hardware Forums.

No rguments with A51's opinions but beware. I have two dead Slimlines in my workshop which have probably died from frying. There is simply no space in that tight little case for any warm air that can't get out so you might benefit from running it as a skeleton.