Life / Living Costs and life in Poznan? [70]

Hello there :)

I'm considering move to Poznan from non-EU (Russia), with my wife and 2 kids. I guess we'll need a decent 3 room flat (or house, not sure). Will 10K Pln/month suffice for supporting 2 kids family? What are tax deductions for having a family with kids, if any?

Any insight greatly appreciated!