What version of PHP does the company have installed? Do a phpinfo() and let us know. If the version is <= 4.2.3, you might be able to use [man]ini_set/man to change the 'upload_max_filesize' directive.
Alternatively, you can set this value in a .htaccess file in the folder this script is running from. Try creating a .htaccess file (or appending the follow line) like so:
php_value upload_max_filesize 5M
The above would set the max size to 5 MB.
EDIT: Regardless of PHP version, I would highly recommended attempting the 2nd solution (involving a .htaccess file), simply because you don't know when the host will upgrade, causing the ini_set() method to stop working.