Help with troubelshooting my engine
 

I have a 2005 Montana SV6 and some one stole all of my gas and my van sits on a steep incline with the nose pointed down. I am handi capped and use my van to transport my wheelchair as well as myself. I say that just to say that I know my battery and electrical system is working, because that works, but I went to the gas station and got 8 gallons of gas and put it in the tank and when I first tried to start my van it turned over for less then a minuet, twice, before I put the gas in it, then after putting the gas in it, I can hear the engine doing every thing but turn over and the gas gage reads 1/4 of a tank and not one of the engine lights are on or any other light that would indicate a problem, but the engine still will not turn over. Does any one have any idea what could be going on? I do not have a lot of money, I do not even have enough to have it towed, so if there is a simpel explination I would sure love to hear it. Thanks to any one and every one who is willing to help me. God bless KIm