The Sole of a Treadmill
Alright, So you only have a tredmill, yet it has trouble with incline?
I should hope that you get that fixed as soon as possible because inclines are you best calorie-butt-kicking friend.
When I was beginning weightlifting, my trainer told me to begin my day with an hour on the treadmill at 10-11 incline and 2.5-3.5 speed. I did the math and this burns more than an hour on the elliptical (For a 5'6, 170lb female)
If you do not get your incline fixed then the best bet is to do a 5 min warm up followed by some fast paced walking. Then ramp it up with 3-5 mins running (if you're just beginning then I suggest 6.0 which is a 10 min mile). Continue to alternate walking, jogging, and running until you've reached your desired intensity level.