It is sent on a line by itself after the GET, followed by a double CR-LF.
if(client.connect(ipBuf,80))
{
Serial.println("connected");
// Insert it here.
sprintf(outBuf,"GET %s HTTP/1.0\r\nHost: www.mydomain.com\r\n\r\n",page);
client.write(outBuf);
}
edit: Insure outBuf has sufficient memory allocated to hold all that.