Hmmm
A combination of Cardiovascular, Strength and power training is the only solution to your leaden limbs lax effect on the slopes.
I suggest Cardio vascular ever 2 days at 60% max heartrate (220 minus your age = max) for 30 minutes at a time. Swimming and cycling are good because they are lower impact on the joints than running. Build this up comfortably and stop if you experience discomfort. Try to vary what you do as you will work different muscle groups and not get bored.
Intersperse this with alternation between some skiing specific plyometric circuits to build white muscle and muscle memory followed by moderate leg weights and then some light upper body action on other days
You should also get yourself on the wobbleboard or vew-do to build strength in your core muscles and joint supporting muscles and ligaments.
What you eat is important too. Try to eat more protein, a 1:1:1 calorific ratio fat

rotein:carbohydrate is good. Typically fat is 7-8 calories per gramme vs. an average of 2.5 for both protein and carbohydrate. Try to eat after you excersise and do not eat after 8 o'clock.
You have to be serious if you want to train. It is also good to get down to the diving boards or trampolines and have some lessons! don't just huck as they will train you to have proper control in the air.
Remeber to take at least one day off training per week.
Good luck and go for it!
If you want some specific excersise then drop me a note
I love gymnastics and trampolines but nothing beats a 'Gymnastic Tramp' for fun