There are some really good posts already, but there are some not so great ones too and I wanted to give my two cents... DO NOT PUNISH YOUR OLDER CHILD (at least not in the traditional sense) for acting out her frustrations. The suggestions about making a special time for her was a wonderful idea. Also, letting her help with the baby will be good for her sense of self worth. You are absolutely right that yelling at her is good for no one. How do you feel when you do it? Probably not good, and she isn't learning a thing from it, except to tune you out when you yell. Learn to use a firm voice that isn't a yelling voice. Use positive language instead of saying "no" or "don't do that." This takes a while to adjust to, but once you get used to it it will be totally natural. Basically, instead of telling her what NOT to do (don't hit, don't throw your blocks, etc) tell her what TO do (use soft touches, blocks are for building, etc). But don't be all wishy washy, either. A great book is Parenting With Dignity: The Early Years. I read it ages ago when I was having a difficult time keeping my patience with a child in my childcare class, and it was extremely helpful. But the keys are to be positive and persistant.
Personally, and my child is younger and not having the same problem, I have personal rules about the way I will behave towards my child. I will not yell at her. I will not give in to ANY whining or crying (with the exception of hurt crying). I will not strike my child. I will not make her feel bad about herself. I will not chase her (unless she runs into the street). I will give her feedback when she accomplishes something, but I will not give her empty praise (nice job! good!- all empty praise). Try coming up with some rules about how YOU will act, and follow those before you put expectations on your child.
Remember, a parent who yells and makes demands will have a child who yells and makes demands (come here, now!- I've heard a child yell this at her mother, and the mother couldn't figure out why? In the next moment she said the exact same thing.
Good luck!