overwriting php.ini settings with ini_set();

Hello,
My hosting provider doesn't allow to change my php.ini file.
I need to increase memory_limit to upload large files with defaulft file browser (TV input file). I know that this is possible with ini_set('memory_limit', '100M'); but don't know where to add this line in php.
Please advice me how to apply those changes to file manager.
Im running Revo 2.1.3, PHP Version 5.2.17

You can do this in the .htaccess file - maybe. It depends on the server configuration if you can change this at all.