If I am reading you correctly, one side of the auger housing is up off the ground and the other is sitting on the ground. The rest of the machine is level side-to-side but not the housing. If that's the case, this looks relatively simple, what with the auger housing being in parts that are bolted and not welded together. I wish they still did them like that.
1. Make sure the machine is on a flat and level surface.
2. Remove the little wheels on the side of the auger housing (or adjust them up off the ground).
3. Check both wheels to make sure they're flat on the ground and that the housing where the motor is mounted is level. If not, this could be your problem. (tires round and even?)
4. Loosen the bolts holding the auger housing to the rest of the machine, see if there's enough play to adjust it and then retighten.
5. If not, loosen the side plates of the auger housing and twist it into position, then retighten them. Might be easier said than done.
6. If all else fails, you may have to rotate the auger housing and drill new holes to bolt it. Can't see how this would be necessary unless it was made crooked.
Keep your eyes open as you do this, you may see something that I can't see (the diagram on Sears' site is very poor) that will help - such as something bent or twisted.
Let us know how you make out.
Who the hell let all the morning people run things?