A cruciate ligament 'snap' is a HUGE injury.A 'career ender' for most footballer's.I'm not insulting your intelligence here but you have been given the all clear by the physician's who treated you to start running and training again?If so i take my hat off to you for coming this far after enduring so much pain and misery!
Firstly,your 'people' are correct a weight of 76kg for a man of 5' 11" is fine.
Secondly.I'm a bit miffed as to how you are only burning off 80kcal after an 11km run!!!That treadmill is in dire need of some serious recalibrating!
Thirdly,on the protein issue,i would of thought it would be a weight 'increase' due to synthasis into muscle mass if you are lifting a significant amount of weight.
And with regards to toning and tightening your abs,there is a wide veriety of exercises you can do.Take a look at some of these:
Bodybuilding.com - Exercise Guides Database.
Pay particular attention to 'Air bikes'.They are extremely effective but must be kept up over a period of time along with a good,low fat,carb moderate diet.