Unless you can get to the speaker connections on your TV, this process is virtually un-doable. Plus, even if you do get to the connections, keep in mind the TV speakers are only designed to handle a few watts of power. I'd recommend waiting until your main speakers arrive. Seriously.
If you're in a real pinch for some sound - and to start using your receiver, head to CC or Best Buy and grab a cheaper pair of Sony speakers. They typically have these on sale for $19 or so each. This would be about the most simple solution at the moment - other than using a pair of headphones.