\documentclass[a4paper,12pt]{report}
\usepackage{psfrag,graphicx}
\begin{document}

\includegraphics[width=.5\textwidth,angle=-90]{gamma.eps}

\psfrag{rh113}[Bl][Bl][1.0][90]{\footnotesize $^{113}_{45}$Rh}
\psfrag{ru113}[Bl][Bl][1.0][90]{\footnotesize $^{113}_{44}$Ru}
\psfrag{ener}[t][]{$\gamma$-Energie [keV]}
\psfrag{cnt}[t][][1.0][-90]
  {\rotatebox{90}{\hbox to 0pt{\hss counts\rule[-5mm]{0mm}{1cm}\hss}}}
\psfragscanon
\includegraphics[width=.5\textwidth,angle=-90]{gamma.eps}

\end{document}