With liquid damage there's simply no way to tell the extent of the damage. You're lucky it works at all, see a couple of other recent posts on this forum of some people who weren't so lucky. The only real way to assess the damage is to pull the MLB and everything else to see how many corrosion blooms you have and how big they are. If you don't have any yet... You will. Odds are your system is living on borrowed time as it is, and is not long for this world. I would suspect within days you will have a rapid escalation of issues up to complete and total death of the unit.

So, might not be a bad idea to grab yourself a new unit before the stores close for the holidays. If the HDD survived, you can just swap the two out and be on your way. And you may as well buy a new one, since the warranty is now gone on your current unit and repair costs will probably be virtually the same as a new unit. Plus, unless you luck out and find a place with an Early 2011 MLB in stock (which would be very rare, since they cost $800-$900), there's no way you're getting this fixed before Tuesday.

And I'm not positive, plus you don't really elaborate, but I don't believe Apple does audio over MDP/Thunderbolt. I'd have to double check, but at least on the older LED Cinema Displays, the audio was sent over USB, not MDP. So, if you're hoping for an all-in-one cable solution for audio and video, not sure it exists for a Mac laptop. But again, I'd have to go back and double check the specs on the thunderbolt models.