my word of advise,
1. Lean forward like what the guys here are telling ya
2. Believe that you can cycle up that hill
3. Find a suitable gearing and cycle up as slow as your heartbeat can take and lock on the pain
4. practice and practice and practice by riding more

Derrr...because I can't carry as many people/bikes on an ATV as I can in a Ford F350 Diesel?

put your thumbs in front on climbs. your body will follow, as you do your pedal strokes, into a more naturally balanced position and allow you to use a smaller gear than you are using that causes you to run out of "legs". this will also help you build up more strength, balance and confidence.
let some air out of your back tire if you are running high psi,the lower the better.
if you dont make it, go back and try it again while its still fresh in your mind but dont have a "I cant do this" attitude or you will prove yourself right.