Your brother is 4? I know you have to be around the age of 16, give or take a couple of years (because of the sound of your post). I only read the first 5 paragraphs or so... so you may have touched upon this....(sorry, didn't feel like reading all that other stuff) I did however scroll to the bottom and read your final question about moving the PS3 to your room.
Your brother is 4 years old and doesn't know any better. Trust me, he really doesn't. Your mom feels bad and guilty sometimes because she feels like she shows your little brother more attention and love than she does to you anymore. I know it might be awkward and uncomfortable, but ask her. Ask her if she feels that way.
I'm also going to guess you have another sibling (possibly older?) (remember, I only read the first 5 paragraphs, if my post isn't making any sense, you can just ignore it). Your mom wants peace and quiet.... and she finds it much easier to just tell YOU what to do because you will actually listen, rather than trying to yell/force/explain to your little brother why he needs to calm down and behave himself. She does this to you instead because she is just tired..... it takes a lot of work and sacrifices to be a parent and she just want to do things the easy way some times. That is why it seems like she focuses all her disciplinary actions toward you (it's easier to get you to listen).
As far as moving the PS3 to your room. Be patient. One day none of this will even matter and you'll be over it. Maybe you can find games to play with your brother. You'll just have to be patient to play the games you want to play. Even if it means waiting a year or 2. That's what I do with most games (but because I wait for them to drop in price). I have a niece to is turning 3 in a couple of months and I can't wait to start Little Big Planet with her and play through that game all over again. Am I worried about losing playing time on GTA V? Or another awesome game that's out? No, because of patience.
I know I rambled on and I've said things you've heard before...... but really..... patience. One day you will be living on your own (hopefully, not a personal shot at you, just saying) and you'll be able to do whatever you want (until you get married, then you get to do whatever SHE wants lol).