I come from a totally different angle. I don't believe in learning to forgive. Emotions are just energies and they can be quickly cleared. It is very important that you clear these feelings because they will affect your health and the way you deal with life in general.
In my opinion conventional psychotherapy is a waste of money. There are self help methods that are far faster and effective.
EFT is free to learn, just type it in your search engine and you will have 1000s of websites to chose from.
If EFT doesn't help there are deeper modalities such as Be Set Free Fast, or the most powerful Inner Influencing developed by Paul Gleblick. But the latter will cost you some money, but less than a single visit to a psychotherapist.
A psychotherapist that practices EMDR is somebody that could help you. But try EFT first, it won't cost you a penny.
One additional note: your subconscious is trying to protect you by not forgiving. It is constantly reminding you that your uncle is a sick and dangerous person.