Mission impossible

czyli - in other words / or / that is
wyżywić - to feed, subsist, keep oneself
za - in this case it means for, ie.: You can buy it for 2 pounds.
zł stands for złoty which means gold/golden, as you probably know it's Polish currency
miesięcznie - monthly (miesiąc - month)

An average Pole is a special agent fulfilling his mission impossible every month. What a skillful nation we are!

If you wanted to translate that sentence it would be: 'or in other words how to feed/maintain your family for 1000 zloty a month'. You would use the word 'your' to describe the family, whereas in Polish we don't do that as it is rather obvious that this is your family. Similarly, in the following sentences:
I've lost my ticket. - Zgubiłem bilet.
Wash your hands. - Umyj ręce.
Take off your coat. - Zdejmij płaszcz.
But we would say:
Kocham moją rodzinę.
Tęsknię za moim bratem.
Lubię mojego nauczyciela geografii.

It's quite complicated. I will explain it in depth in a future post.