I had a long post wrote out and I closed it like a spastic.
to me the biggest flaw with something like stronglifts is eventually its going to be too difficult to recover squatting that much a week without the aid of steroids. Now your squat isn't bad for your bodyweight it is smack on what is considered a novice lift which is about where 6 months of training would get you.
http://www.exrx.net/Testing/WeightLifting/SquatStandardsKg.html (for reference)
So thats nothing to be ashamed of. Considering how strong your bench is (you are getting towards the intermediate class with that one) I would guess your issue is technique with your squat. In general stalling is caused by lack of muscle recovery (are you eating enough food are you getting enough sleep) or technique. That said with all success beginner programmes there is a risk that stronglifts and the like become a bit of a mantra. What I would possibly suggest is that you switch it up and attempt a short term goal orientated routine like westside.
http://www.muscleandstrength.com/workouts/modified-westside-barbell-strength-workout.html
You could just be in a funk from doing 6 months of the same routine. Westside is designed to go over 8 weeks with the goal to increase your 1rm. After the 8 weeks you can switch it back to strong lifts, try Wendler or if you want to you can train something designed more for muscle hypertrophy than strength.
