ATI Radeon HD 4200 Low Budget Upgrade

[pkbw]

I'm looking to add a dedicated graphics card to my PC to hopefully improve performance.
I'm willing to spend around 100$ or less.
I'll mainly be gaming on it. I can run LoL on low settings, but i'd like to play more games than that.
Specs:
HP Pavillion P6620f
AMD Phenom II X4 830
ATI Radeon HD 4200
6 GB RAM
N-Alvorix-RS880-uATX (CPU-Z says foxconn 2ab1??)
250 W Power Supply
1600 x 900 Display

I'd prefer to not have to upgrade my power supply. Will there be a decent increase in performance?

 

[DComander1x]

I'm looking to add a dedicated graphics card to my PC to hopefully improve performance.
I'm willing to spend around 100$ or less.
I'll mainly be gaming on it. I can run LoL on low settings, but i'd like to play more games than that.
Specs:
HP Pavillion P6620f
AMD Phenom II X4 830
ATI Radeon HD 4200
6 GB RAM
N-Alvorix-RS880-uATX (CPU-Z says foxconn 2ab1??)
250 W Power Supply
1600 x 900 Display

I'd prefer to not have to upgrade my power supply. Will there be a decent increase in performance?

A simple EVGA / Nvidia GT 620 would be a very noticeable increase in performance and can run on the 250w Power supply you have. Also, its only around $50 or so. I have that very same motherboard & Power Supply, and I upgraded to a GT 620 and it ran most games at medium to high settings just fine.