I have 1024x768 resolution, i set this in the user.settings but still black barrs, why i can do? i really want play the game in a filled window…
1024x768 is really small for this game.
Your problem is that the game is wide screen and your resolution is not, that is why you are seen black bars (at the top and bottom, right?)
I think there is not much you can do. It is like trying to fit a rectangle into a square hole.
changing my resolution can reduce my fps in the game or not make diference?
I’m going to guess that higher resolutions takes more processing power. Not sure if it is noticeable though.
i really hope a version with 1024x768 support, Almost all games nowadays have the support for this resolution. 
I doubt it. We are entering a time where 4K is considered to be THE new resolution. This means a very basic resolution as Full HD is going out the window, nevermind just HD, or a non-wide screen like yours.