I'm not sure you can really do anything with the way you have it set up. I'm actually surprised your system is working as it is, the 5570 needs a 400w supply. Mind you, if you're never stressing it, you can get by.
I'd really REALLY recommend upgrading the PSU to a good name-brand in the 400w range before you consider upgrading the CPU.
Anyways, with that system, there are quite a few different versions hanging around. Can you download CPU-Z
, run it, and check the motherboard info? The CPU support will vary by motherboard.