Do you have shared hosting? Or do you have root access to your server?
If you have shared hosting, you would need to contact your host and ask them, but 9 times out of 10, they wont raise it.
If you have root access, you need to find the location of the main php.ini file and do the following edit.
Find:
upload_max_filesize 2MB
Change the 2MB to something higher.. (Just don't go wild crazy)... Maybe something like 12MB or 20MB.. Maybe 50MB...