Law / I want to establish new small company in Poland (Warsaw) [6]

I want to establish new small company in Poland near Mokotow, Ursynow in Warsaw.

So I want to hire engineers(3-5 years mobile communications sales engineer ) and admin (3~5years).

I have no information about Poland recruitment market. Somebody can help me to get information.

1. How much will approximate salary?

2. How much will the fee Head-hunters or recruitment agency?

3. or do you know good recruitment company ?

I really want to your help..Please....

Thank you.