FSP saga ii 350W is a good PSU for your budget and it should handle overclocking as well.
Also, its better you go for HD 5670 512MB for 4k instead of 4670. It performs better, consumes less power and is more likely to be available.
@thetechfreak I don't think that 500W is required for his config, even with OCing. If it would have been a higher graphics card such as 5770, then 500W would have been a better choice.