Thanks for your advice.
I had it already, as well i downloaded GPS Status (seems to be a bit better than sensor tester). I went out today and GPS Status caught 5 satellites, but couldn't determine my position
, after that i've switched to g.maps and after a while, my position on the map was ... my home's address (that's were i used internet for the last time) - two streets from where I was standing, so after that I've switched again to GPS Status and within next 15 minutes couldn't catch any satellites. Have no idea how to fix it....