Training this winter

70kg squat is a bit flimsy - if you really want to strenghten your legs you should be startting your winter weight training about 90-100kg and aiming to imrove in 5 kg increments till you 'top out' in March. A good improvement would 100 to 135/140kg.

Deadlifting is also very good but watch your back!

Watch your back?

Get some decent gym coaching from a strength and conditioning coach who can give you great form from the start.

As for 100kg squat - my girlfriend can do that, man up.