Don't judge yourself by a level on a machine. Instead think about how hard you were working. Think of a scale of your effort from 1(easy) to 10(reallly really hard) and you should be working between level 6 and 8 (remember this is how you feel NOT the level on the machine) for around half an hour.
It sounds like you were putting in a lot of effort which is great! The elliptical is a lot harder because you have to use your upper body as well as your lower, and you are using not only your own body weight, but the resistance of the machine as well. Keep going, and each time you use it, try and beat your time or go a little further. This will keep you pushing yourself and increasing your fitness levels.