OK, I found the solution that worked for me at least:
Initially I followed this tutorial: http://forum.xda-developers.com/show....php?t=2085344
After following step by step for many many hours, I did something else. I removed the lines from host file and I stopped that web server.
Somehow(I don't know how exactly - it was 5am) I installed "LG Mobile Support Tool"(I think it has something to do with "LG Mobile United Mobile Driver" tool). Also, from what I remember, i deleted all old drivers.
Then, I removed the battery from phone, pressed the "vol+" button(and hold it) followed by inserting the usb cable; when in s/w mode I added the battery;
Using this tool "LG Mobile Support Tool" the phone was connected to PC, therefore, the application downloaded the original soft from LG site.
The installer began, some magic happened, at 95% phone restarted and an android with a red triangle appeared on screen.
After the upgrade process was finished(at 100% I pressed the power button 'till the phone shut down;
Then I started it; the phone was working fine, original recovery tool was installed, root was removed, but all programs and settings were still there; nothing was lost.