What to do?

Ugh.
Leeara is so frustrating at the moment and I'm finding it REALLY hard to like her :(
She yells at me, has the attitude of a 14 year old, and is generally just an unpleasant little girl.
I can sit down with her to do something, and whilst we are doing it she is always talking about the next thing we are going to do! It's like no matter what I do, it's NEVER enough.
I don't know how to combat this.
She plays up at bed time, so much so I gave her a fucking dummy tonight to shut her up. She went to sleep straight away. Why is my 4 year old so insecure that she needs a dummy to settle? What am I doing wrong? She never used to be like this, she was an absolute angel.
I really feel a lot of her behaviour is to do with Ky, but I just don't know where to start somedays. But I have to start somewhere. So what to do?
What is making my little girl so unhappy? I worry that she is unwell, she has been pale lately, and complaining of a lot of ailments, it's hard to tell whether these ailments are real or attention seeking *sigh* I fear that she is desperately unhappy :( I don't want her to be unhappy.
I do however wish that she would go and play on her own. I wish that she would go and play outside during the day when I tell her too.
I feel like I'm going in circles with her..
So this is where I'm going to start.

-Limit TV time to two shows in the morning. From 9-10am. The darn TV has been on from anywhere between 6-7am until 11 lately, and I am not happy with that.

-Limit my computer time. I've been spending far too much time on here AGAIN. HOW do I get sucked into it? For gods sake, reading how to be a good parent is just stupid, I should be putting it into practice.

-Every morning, spend some writing time with Leeara. It doesn't matter whether it's 10 minutes, but she needs that time. Any suggestions on how to get that time with her when Ky is running around though? He is not likely to go off and play by himeself if I am sitting at the table with Leeara.

- Read her a book EVERY SINGLE DAY. Yes I said it. I am one of those slack parents who rarely reads to her children, and I don't doubt that's because the TV is ALWAYS on, and the computer is ALWAYS on. Why why why am I so damn selfish?

-Give her an extra 15 minutes two on one time every night before bed. Tv off, and playing a came of some sort. She loves playing guess who, and is getting quite good at it! She also loves to play go fish, so I better get a hold of some cards.

I'm sure there are more things, but that's just a starting point. I'm going to trial those things this week and I'll come back later during the week and write about how it's going. Hopefully it will have a positive effect on her behaviour.