I would like to update my GPU and PSU

Hi I'm new to this and this is my first post. I would like to update my GPU. I have a HP Pavilion P6754Y desktop. I would like a nvidia GPU. I use my computer for video editing. I curenttly have a Integrated graphics using ATI Radeon 4200. I use adobe CC Premiere and After Effects. Please guide me to what i need to make rendering and video playback better for my video editing process.

Here are my specs: HP Pavilion p6754y
OS:Windows 7 Home Premium 64-bit
AMD Athlon II logo Operating speed: Up to 3.0 GHz
Number of cores: 4
Socket: AM3
Bus speed: 4000 MHz HT3
Integrated graphics using ATI Radeon 4200

MEMORY Amount: 4 GB
Speed: PC3-10600 MB/sec
Type: DDR3-1333

Here is a liink to my Desktop specs as well. http://support.hp.com/us-en/document/c02628380

You are looking at geting a gtx 750 with that kind of low power psu.
But realy you need a new computer as thats pretty outdated now tbh.

Ok thanks yes this is outdated now but it actually performs well. I will get a new PSU as well. I want to know if i get that gtx 750 would i notice a great difference such as rendering time and video playback while editing? What all could i do to make this computer better? I'm just worried about it performing well with the Adobe products. I'm not sure what to do a new computer sounds good but i really like this one i have. Do you suggest any good computers?

Over just useing a AMD Athlon II X4 640 yes but i'd just save my money and build a new pc throwing money at a pc that dated will only just be a waste.

I understand i didn't realize how dated it really was. Thanks for the help. I will look into building a pc.