"Wireless headphones" come in several fashions:
- old-school infra-red or RF transmitter connected to the source, with corresponding (proprietary) headphones;
- bluetooth headphones relying on Bluetooth technology available in (almost) all phones, tablets, laptops.
iPad requirement almost excludes first option. I don't know whether PS3 has Bluetooth transmitter built-in, however, so you might need to buy additional BT transmitter, and connect it to audio-output of PS3.
As for separate volume controls of left / right (or balance) built into the headphones - I don't think such a beast exists.
You might be able to build custom (bulky) solution consisting of BT receiver, headphones amp (with L/R control), and wired headphones.