sounds like a really steep hill, what car do you drive? it could be that it just isnt going to have enough power.....wel with the clutch fully engaged it seems like it doesnt already (there is a test like this they do at Mira test center..... how far can the car go up a steep as hill before spluttering to a halt and its a proper bad incline sometng that in real life on normal roads youd never come across, most of the cars (mostly 4 pots) never make it to the top)
basically, your gonna have to keep the revs high and ride the clutch..... its not gonna be good for the clutch though. you need to keep the car in its torque band.
failing that, you could figure out how fast you can travel before you hit the hill ? i mean any momentum you can carry onto the hill will help you get up it. perhaps devise a way to basically lessen the change in gradient at the bottom of the hill from the road? like lay some wooden planks or a steel plate between the foot of the hill and the road at the bottom?.... this will lessen the gradient change, should let you attack the hill faster without mullering your cars front bumper
last option. buy a winch, attach to something solid at top, winch your car up my thermo lecturer drives a old skool landy defender with a 4T winch on the front, it can pull itself out of anything
http://uk.youtube.com/watch?v=UMALgzckM9k
http://uk.youtube.com/watch?v=LKpWGy1slVs
even these guys struggle you know