I decided to buy a new CPU and MOBO for my system , because currently my CPU is bottlenecking my gpu , what do you think which would be better: Intel i5 3350P or i5 3570K ( and AsRock Z77 Extreme 4 mobo )
If it's in your budget, pick the i5-3570K. It outperforms the i5-3350P at stock clocks, and of course you can overclock it if you want to. In fact, with 220 euros, you could easily afford the 3570K and the Coolermaster Hyper 212 Evo (a great, cheap cooler) and be able to overclock that sucker as soon as you wanted to.
When I suggested the i5-3350P in your last thread, I did so as a budget friendly alternative to the 3570K. If you have the chance to get the 3570K over the 3350P, take it. You won't regret it.
Edit: If you can get the parts CTurbo linked in Germany, then go for those. At those prices it's practically stealing.