Different modules width on mainpage

Hello, I´ve installed Joomla 2.5 according to your instructions and when I configure the main page by the appearance of the main page of the demo installation, have my modules on the left and right side with larger width, so the middle image and text overflows to the right module. Where can I set up a smaller width module to the left and right? According to the source code of the demo installation modules have 240px width,but 285px on my installation. Can it be changed in the administration, or only in CSS?

Can you send us link so we could check that.

vmuller.cz/hotrestaurant/

You have :

Left Column Width
Right Column Width

parameters in template settings under Template Layout group

Thanks a lot.