With the motherboard there are many more things that need to be considered: mATX vs. ATX, onboard i3 support, USB3, SLI support. This is the cheapest P55 board I could find that explicitly supports i3's. ~$125
Altogether it comes to ~$640. I'm not familiar with the site or the language so that is before any discounts or shipping.
If you need a PSU, I would go with the Xigmatek NRP-PC502. It is more than powerful enough, with high efficiency, and has two PCI-E connectors. It's never a good idea to skimp on the power supply. You could make due with one of the 400W Corsair models, but you would have to use a 4-pin molex to 6-pin PCI-E adapter to install a GTX 460. ~$90