Fatal Error when autoupdating WP 2.8.4 es

There is a new version of the spanish version of WP and when I try to autoupdate, I get this message:

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 2573113 bytes) in /home/myrootdirectory/public_html/wp-includes/http.php on line 1327

I’ve never done a manual update so I am not so confident to delete all my files, except the ones I’ve changed, and write the new ones.

Is there anything I can do about this.