(or whatever you like. Specify the path only; leave out php.ini)
Actually, you don't need it. By default, it will look for php.ini in the "etc" directory where you installed it. In any case, phpinfo() tells you what php.ini file it's using (near the top of the page.)
Are you sure you compiled it as an Apache module on a shared server? That sounds somewhat impossible. It's normally compiled as a CGI.