Can I store a fresh turkey in my garage for a few days?
As setek said in the comments, 43F is too warm. Anything above 40F and you only have a couple hours before it's unsafe (has the potential to make people sick, even if unlikely). And your garage is attached to a house that's well over 40F, so it'll probably be well above 43F in there.

So you really need to keep it chilled. If you don't have space in your fridge, you might be able to make do with an ice chest; if it's really at most 43F, the ice will last a long time.