Assuming you can get the hose in far enough to hit the remaining gas, another siphoning technique is to wrap your hose in a plastic bag around the opening to the gas tank and seal it. Then blow into the tank through the hose end to pressurize the tank. After about 5 seconds of this, stop blowing and lower the end of the hose to your bucket.
This technique should help keep you from sucking up or inhaling gasoline. Since modern cars typically have a fuel recovery system, this technique could damage the charcoal canister and trigger the check engine light.
I've never tried it, but there's supposed to be a way to disconnect a hose from a fuel injector and turn the ignition to on to pump the gas out. Sounds like a bit of a fire hazard.
You may be able to add some gas additive to the tank that will enable it to start and burn the bad gas. HEET for example is supposed to remove water in a gas tank.