Real Estate / Rental market in Warsaw, are prices increasing or decreasing? (2 room apartment) [10]

Merged: Small office & Sales Executive Required - what salary in Warsaw, Poland? Cost of a 2 room flat per month.

Dear Members,
I want to start a trading company in Poland.
To do so Initially I want to take a 2 room small office in Warsaw where I can stay and manage my business in the initial stage. I also need a sales executive.

Would you advise what can be the cost of a 2 room flat per month and salary of a sales executive per month?

Would appreciate any reply