Everyone has given you great advice, I'd just like to add that I would change up your cardio a bit. I used to be really winded on the treadmill at first too, but the only thing that will fix that is pushing yourself a bit. Your incline is way too high, bring it down to about 1.5% or 2%, anyone would get winded doing 11.5.
Also try this, for your first 2-5 mins walk at speed 2, then for the next 5-10 minutes push that up to 2.5. If you can, do the next 5-10 at 3, and then come down again to 2.5 and then 2 if you need to. The more you push yourself the easier it's going to become, and if you can only do a couple of minutes at a faster speed, that's fine, slow it down again till you catch your breath and then speed it up again. After 1-2 weeks of doing this, I'm positive you'll be able to do around 20 minutes at speed 3 with no problem, I mean it will be a workout, but you won't have to stop. (Then you're just a hop skip and jump away from actually running on the treadmill
)
Also pay attention to your heart rate, you want it up to where you're working hard, but not so hard that you have to stop. Good luck!
One last thing I do to help push me is, I create a playlist on my ipod specifically for the treadmill. At about the 13-15 minute mark (about 3 or 4 songs in) which is when my mind starts to wander, and I really want to get off, I put a song that always makes me want to dance, since I can't really dance on the treadmill, I find I always start walking a little faster lol, and that pushes me through the next 4 mins. Once I see 19 mins past, I'm like bahhh, only 10 to go, I got this.