If you can overhead press 55 Kg then that means that you can at least get that amount of weight into position for a squat, so you may want to try a high-rep squat program (20-rep, etc.).
Since you are at a point where consistency and work ethic are going to make the biggest difference I would just look for a program that is balanced and easy to follow. Do not worry about a lot of complex exercises or protocols - just focus on pushing yourself and allowing for ample recovery when necessary.
I have a 3-Day and 4/5-Day template posted in this thread which may be of interest to you, but there are plenty of other good options out there as well. My advice would be to choose a program that is written by someone reputable, and then I can help you to tweak things to meet your specific needs/objectives.
Hope this helps.