I have lost my Samsung Galaxy Ace
If it's turned off, you most certainly can not turn it on remotely, do there's no helping you.

If it's turned on, you could try activating an alarm from Google device manager, if you didn't deactivate it earlier. Go to Google device manager and click "alarm"; the sound may help you find your phone. The GPS data indoors is very inaccurate so it is of no use; it would only tell you it's in your room, which you already know.