There is no free parking at this venue, but you've got a wealth of great transport options available. It's a stone's throw from Deansgate and Oxford Road stations. A 15 minute walk from Manchester Piccadilly station. And a hop, skip and a jump from the metrolink station right near the entrance which connects to all over Manchester.
If you're determined to come by car (can you bring a pin too?!) then I'd suggest checking something like
JustPark for your best options, mostly all of which are cheaper than the NCP car parks if you book in advance. Change the date/time as necessary.
Hotels are of course all over Manchester. You might want to consider staying on the outskirts where you can park for free and then ride the Metrolink in?
Can't wait for this one. Massive new venue right in the centre should make for a fantastic event!