You can log into Ecas with the 'R********' number on your receipt with the sponsor's details. As far as I know people get their dates from there, unless they are waaaay more patient than me and are waiting for letters/emails.
Once sponsorship is approved it should show on Ecas as 'decision made' and a letter will be sent to you. The next update will be when your local office starts processing and it will show 'in process'.
Lots of waiting & hoping I'm afraid!!