How often should I be increasing weights?

mayfly00

I lost the baby weight and now I'm trying to get fit. I've just been doing cardio for the past 3 months, but 2 weeks ago I started a weight machine routine that I'm doing 3-4 days a week (every second day). I also still do 20-40 minutes of cardio every day. I'd like to gradually build up strength and increase my weights. What kind of goals would be reasonable? I'm 24 years old, 5'11"/125lbs, if that makes a difference.

This is where I'm at right now:
-leg press: 135lbs
-chest press: 30lbs
-seated row: 40lbs
-shoulder press: 30lbs

Thanks!