Inexpensive Audio remote controller?

My wife thinks we lost the audio remote controller for our built-in wireless headphones in our '04 Sienna van. The dealer wants $160 for it!! Is there any other options? They also want $80 for another headset (which we haven't lost yet, but thought we might get just in case), but we found those online for $45 elsewhere. Therefore, we're hoping there's a better deal on the Audio controller as well.

Is there any way to just get a part # for it so I can do some better searching? I can't find anything on froogle.com or ebay for just "Sienna Audio Controller"

Thanks!

Update: Luckily, we found it, but it still would be nice to know if there's another option if we lose it for real later (Or just want to buy a 'spare')