\documentclass[a4paper,twoside]{report}
\usepackage{polski}
\usepackage[utf8]{inputenc}
\usepackage{fancyhdr}

\pagestyle{fancy} %% deklarujemy styl "fancy"
\fancyhead{} \fancyfoot{} %% "zresetuj" zawarto¶æ pagin
\renewcommand{\chaptermark}[1]{\markboth{#1}{}}
\renewcommand{\sectionmark}[1]{\markright{\thesection\ #1}}

\fancyhead[LE,RO]{\normalfont \small \thepage}
\fancyhead[LO]{\normalfont \small \itshape \rightmark}
\fancyhead[RE]{\normalfont \small \itshape \leftmark}

\fancypagestyle{plain}{\fancyhead{}\renewcommand{\headrulewidth}{0pt}} 

\begin{document}


\chapter{RozdziaƂ pierwszy}

\section{Punkt jeden-jeden}
a\newpage
b\newpage
\section{Punkt jeden-dwa}
x\newpage
y\newpage
z\newpage
p\newpage

%% %% %% %% %% %% %% %%
\chapter{RozdziaƂ drugi}
\section{Punkt dwa-jeden}
q\newpage
r\newpage
s\newpage
t\newpage
\section{Punkt dwa-dwa}

\chapter{RozdziaƂ trzeci}
\section{Punkt 3-jeden}
w\newpage

\section{Punkt 3-2}

\end{document}