It depends on nature of the alimony granted. If it was for 'three years' that implies that it was limited in time meaning you probably cannot extend it. You need to determine if your alimony was 'in gross' or 'periodic' and if it was periodic then you may be able to have it modified based on changed circumstances.
You should consult with your attorney from the divorce or another local attorney to see if the alimony can be changed, and if so, what the best procedure to follow to have that done is in your county.
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