It's possible to have single-column figures and tables with captions, but you might have to fiddle with the placement because they won't 'float'. Put the following before \begin{document}
\makeatletter \newenvironment{tablehere} {\def\@captype{table}} {} \newenvironment{figurehere} {\def\@captype{figure}} {} \makeatotherthen use figurehere and tablehere where you'd normally use figure[h....] and table[h...]