Since you are now playing the youtube vid on your PC I doubt there is an option to use the "send to tv" option anymore. The best way I'd suggest is to use a wireless mouse keyboard for playing videos from PC and pair it with the ipad to play content seamlessly in case you want to continue watching the video while you get going. I keep my ps3 and laptop connected to my AVR when at home. I mostly use my laptop as the hub to play all media content.
- using the youtube apps on ps3 and my phone keeping them paired
- using the laptop as a DLNA sharing hub and play content on the console and mobile devices wirelessly