Ankle ligament reconstruction

Hello, I was wondering if anyone could help me with some advice.

I have had lateral ankle ligament reconstruction and ganglion removal and currently 3 1/2 weeks post op. i am in an air cast (which is not that comfortable on a night!). I have been advised to keep this on until my fall up in just over 2 weeks. the question is i have major muscle imbalance in my leg and after the cast comes of i will be scared of going over on my leg, would it be wise to purchase a small ankle brace to use once the brace is off when i am at work or out of the house? If so i want to get one to use straight away would there be any recommendations? Finally- sorry to go on.... but how what are the normal time scales for rehabilitation on this?:D