Allowed memory size of some bytes exhausted

Hi!

I am using Joomla-Visites 1.1 RC2 since november and now when I try to see the Monthly statistics I get the following error:

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 1202835 bytes) in /my_website_path/administrator/components/com_joomla-visites/core/include/Archive.class.php on line 163


Can anyone help me? where can I upgrade the allowed memory?

Thanks