My toddler cries over everything and seems to really dislike her baby sister

Sounds like a normal 2 year old to me. dont lose heart it wont last forever.

but also, it seems like you are expecting too much out of the 2 year old. yes you have other, smaller children who need your attention, but your 2 year old cant be self sufficient in anything yet.

stop 'getting onto' your 2 year old.
and definitely stop the yelling. you have to yell to get her to answer because that is what she is used to now.

all children are different, and while there is nothing wrong with how you are parenting right now, it is obvious it does NOT work. try a new approach. reward the 2 year old for NOT pushing her sister. reward her for NOT taking toys, and reward her for sharing her toys. reward her EVERY chance you get. see if that works.

for 2 year olds, stickers on a chart works well. or M&Ms, or let her earn marbles in a jar (make it fun too, let her decorate the jar) and add a marble for each good deed.

and dont forget to make things special for her sometimes too. the marble jar can be JUST FOR HER. and make sure you take special private time, with just mommy and daughter with both your 2 year old and 1 year old.

and DO NOT be afraid to punish your 1 year old. because even though you dont mention it (because you are frustrated with your 2 year old, i understand absolutely) but even though you dont say anything here about it, i KNOW your 1 year old is instigating some of this. because thats what 1 year olds do :P lol. dont let her get away with picking on her sister either. its a 2 way street. sisters fight. :P its a hard job to balance everything with 3 children. especially with the younger 2 so close together.

quit letting your 1 year old get away with being a butthead to her sister. she DOES know better, and she CAN learn not to do it. you are basically showing your 2 year old that sissy is allowed, but she is not, and its not fair. if the baby pushing the 2 year old, discipline her for it. if the 2 year old pushing back in retaliation, absolutely get on to her for it, but also reiterate 'i know sissy pushed you, but come get mommy if she does, dont push her back' and also help her see that she is the BIG sister, and she should set a good example for her baby sister.

you dont mention any problems with your oldest, but i thought i would mention, in the midst of all this hectic toddler-ness, dont forget about your 9 year old. my daughter is 8, and still very keenly feels jealousy sometimes (over cousins and such) make sure to take private mommy and daughter time with her too

I hope i helped some! good luck!

Jenniepepsi gave you a great answer. The only thing I would change is the M&M reward. Food rewards at this age--especially sugary treats--are a bad precedent leading to unhappy food choices later on.

I've been watching my daughter deal with almost the same issue (hers are one of each, boy and girl) and honestly, sometimes you just absolutely need to pick your battles. No, it's not good for one child to pick on another, but they're vying for a spot in the pecking order. There will be moments when, say, making the 1-yr-old pick up her sister's blocks that she's just knocked over will be a viable choice. Other times it may be best (as long as they're not actually hurting each other) to just let them duke it out on their small-fry level and just keep reinforcing that they are sisters and need to love each other. You'll go deaf hearing yourself say that, but in the end it does make a difference. Believe me, making the 2-yr-old toe the line because she's a smidge older while the 1-yr-old gets off almost scott-free is going to bite you back later during potty training. There's nothing harder to train than a little girl who's got a grudge because she feels she's being treated unfairly.

Good luck to you! And as Jennie said, it will all level out in time. Try to maintain your sanity while you're waiting.