I feel exactly the same anger as the OP does. What happened to me in my life may not of been as bad but i'm constantly angered by my past events and we are all human so you're not a bad person imo. Unlike alot of people, i get my revenge. If i've been screwed up as badly as you have then i have and still do get revenge. Bricking windows is 1 way, it's best to do it at 3-4am and make sure you have an alibi. Fighting them in the streets is not a good idea, they will probably have alot of mates and the only way you can beat them like that is if you know more people or respected thugs. It's sad to say, but this is how society is these days. If you plan on getting revenge, make sure you make the limts, don't get carried away and getting caught or do something you regret.
Also, plan when you are calm, planning when you are anger leads you to do things you'll regret. I may sound like a pyscho lol but i'm not, i've bricked a couple windows in my past and fought thugs in the streets. I respect myself for standing up to chavs or even racist goths [yup they seem to hate me because i'm quiet and listen to urban music] -> big generalisation there but some chavs are cool just like goths it's just they seem to cause me trouble. Good luck and i'm sorry for your loss, if you can, try to recover without violence. 2 wrongs don't make a right and step by step i'm doing my best to challenge my anger in sports and other positive stuff.