Hi Courier,
I had a much milder injury compared to yours and it took me about 3 months to ditch the crutches and another 3 before my walking returned to "normal". My ankle was incredibly swollen also and this was my major issue (along with pain on weight bearing). Typical healing times of lower limbs are 12-24 weeks, and going by you injury, my guess would be you would be in the latter timeframe.
In terms of medication it does seem like you were on quite a high dose, and strange the surgeon didn't do a clinic review, but perhaps things are different from how things are done in NZ. From a physio perspective you need to have enough medication to enable you to perform the exercises prescribed by the physio - as this is vital that you get your range and strength back. For me I tried accupuncture, and further down the track went to a massage therapist for about a year before the swelling / scar tissue in my ankle went down. Everybody is different of course and as long as you are managing the exercises prescribed by your physio you should be on track to return to function - but it is a long process unfortunately.
All the best with yourMRI scan and don't forget to discuss any concerns you have with your physio.