How can I get off of this Seroquel the best way?

I need to get off this seroquel 300mg.at bedtime for bipolar due to high cholesterol and weightgain.  I was given neurontin 300mg.and ambien CR to take at bedtime and lowered the seroquel to 200mg.  I was suppose to be tapering off but had to discontinue the neurontin and ambien cr due to extreme pain I experienced either from the neurontin or coming down on the seroquel.  I went back on the seroquel.  I am so frustrated trying to get off of seroquel.  It has me a prisoner.......and the bipolar is hard to deal with but my physical health is failing.   Ambien CR is good and keeps me sleeping longer than seroquel but do doctors prescribe it for long term use everynight instead of just prn?