You've got a rather complicated knee going on there! I had a arthroscopy in June 2011 with a patellar debridement and a lateral release, that didn't help much so on the 21st of August this year I had an MPFLr with a fantastic surgeon down in Cornwall.
The first thing is that it sounds like your confident in your surgeon, that's fantastic, so many people end up seeing someone who just doesn't understand their problem but it sounds like your guy has explained your knee to you well.
I don't know how much you've been told about your MPFLr but I didn't know too much about the recovery before the op so it was a bit of a steep learning curve afterwards. Have a look at this link, I found it to be a really good explanation and pretty good in terms of what to expect for rehab afterwards: http://www.royalberkshire.nhs.uk/pdf/MPFL_oct101.pdf
Have you been told if you'll be in a brace or not afterwards? I wasn't because my surgeon doesn't think they're necessary, I was told the graft was really strong straight away (I had hamstring tendon put in) and they had me bending it to 90 degrees before I even left the hospital. I'm 6 weeks post op now and I've had full bend and extension from 4 weeks which my surgeon is thrilled with. I'm also fully weight bearing as of about 3-4 weeks, but very very slowly!
I will warn you that you are likely to be in shed loads of pain after the operation, but it will get better! I was in hospital for 4 days after my op and on morphine for 3 of them, after that I came down to a strong dose of codeine with diclofenac and paracetamol, and now I'm pretty much down to over the counter painkillers and everyday the pain gets that little bit less.
So far I've found the results of the op to be good, my knee seems much more stable and hasn't subluxed once (it used to go every time I straightened it out, so every other step!), so that is a major improvement!
One thing I've found, which sounds obvious but apparently loads of people don't do, is that you have to be majorly strict with your physiotherapy afterwards. Like you I had been struggling for a while before the op (crutches and braces and then more braces for 2 years) and my muscles were pretty wasted even going into it. I was told to do hourly exercises and I have been religiously, and everyone is really impressed, physios and surgeon, with the progress I've made so far. Don't get me wrong, in the days and weeks after the op the physio HURT, but the results I'm seeing already make it well worth it.
You mentioned sleeping at night, don't be disheartened when your sleep quality is awful for the first month or so because it will be, just battle on through because again it will get better. If you can ice your leg for an hour or two before bed it really helps you get to sleep initially, and make sure you keep on top of your pain relief, theres nothing worse than sleeping through your 1am does and waking up and 5am in agony!
Anyway, long post! If you have any questions or just want to chat please just ask.