Yes, that motherboard has a pcie 2.0 slot, any pcie 3.0 card is backwards compatible with previous pcie, there's no bottleneck with a 2.0 pcie at 16x.
Also that cpu will not bottleneck the 650 ti.
Any decent psu with 400W will do.
Without knowing the country i can't, there's several euro countries with the euro currency.
What i can tell you is this, look for a decent psu within 400-450w, from brands like antec, corsair, fsp, seasonic, xfx, ocz, pc power and cooling, enermax, silverstone.
See if you can see any psu with the wattage rang and of any of those brands for 50 euros.