just squat or full leg day? Strictly for strength, Squats and a Deadlift variant (to balance quad and ham strength) would probably be enough. Lunges, if done heavy, will help here also. You might want to search through the 'powerlifting' forum for some more-specific advices.
just squat or full leg day? Don't get ya panties in a twist...lighten up. Bottom line, to get stronger at squats you're going to have to squat more. doing a program like SS will achieve that. I started at 145lbs 3x5 finished 4 months later at 275lbs 3x5, 166lbs to 185lbs and still wear a size 34 jean, not skinny ones though, lol.
just squat or full leg day? who cares what jeans you wear bro keep going lol you got a nice base to start with im sure jasonk^ legs are about the same lol jk go do starting strength the right way and come back and show us pics in a month