Hello Elisabeth,
A good website to read, if you haven't done so yet is
http://www.stumptuous.com/weights.html
I do have a few comments about your current workout.
I would highly recommend doing weights before cardio or on seperate days.
I don't see a workout for your calves and I also don't see variety in your workout but some people switch workouts every few weeks, some more often, some less.
As far as free weights vs machines, free weights have their advantages in that I think you do more muscle work but machines have their advantages as well, one being that they generally encourage form better.
I would also say don't worry about being perfect (what is perfection anyway?) but rather get comfortable with the weights and as you get better, you can add/modify your program to suit your needs.
I hope this helps.