In trying to set up my new ipad to play through the car's sound system (via Bluetooth) I lost my phone's connection. Does this mean that I can only connect one Bluetooth device at a time?
It can only connect to one at a time, but it will remember many. It doesn't grab devices in any order. Turn your Ipad off and it will connect to your phone.
it should let you connect your iphone as phone over BT and ipad as bluetooth streaming audio at the same time if thats what you want
I have encountered a similar problem with my phone and an iPod Touch. What I found is that sometimes the Prius connects to the iPod as a phone, which locks out the real phone. For now I have unpaired the iPod.