Thanks for the responses.
@kyraiki my resolution is 1920x1080 and budget is around $400
Swap your HD5770 out for a Radeon HD7950. Then invest in a CPU cooler to OC your i5, that should give you a very nice upgrade
The Radeon HD7950>GTX660 Ti due to the performance the HD7950 can achieve at a $300 price point. Also, the crippled memory bandwidth may alter the GTX660 Ti's performance if you're an Eye-candy person.