You should have sent that with the inland PR application - provided you had legal temporary status when you filed it. Since you didn't, you're going to have to wait until you receive first stage approval (6-7 months after you filed your application) and then you'll be invited to apply for an OWP. It's really difficult to send an OWP ap separately from an inland ap and have them match it up; and if they don't, they'll try to process the OWP application prior to your getting first stage approval, which means you won't be eligible and they'll refuse it.
In the meantime, hopefully you had temporary status when you filed your inland ap or it could be sent to your local office for processing, and that can delay your first stage approval. If you still have valid temporary status as a visitor, send an application to extend that status BEFORE it expires. That gives you the right to remain in Canada until they make a decision on it. Be sure to include proof that you have a qualifying relationship and a PR ap in process.
As I said before, you shouldn't expect any response from CIC on an inland ap until such time as you receive first stage approval - 6-7 months after they receive the application, if it's a straight forward ap and you had legal temporary status when you submitted it. Otherwise, you'll receive notification that it's been transferred to your local office. Your sponsor can contact the Call Centre if that happens to find out what the local office timeline is.