Looking to build a budget PC

I'm starting to see my PC struggle to handle some newer games and figured its time to upgrade. I don't want to spend any money above the 3 digit numbers ($999 being the max) I need a new monitor, keyboard, and mouse. I don't want to have a huge PC so I've decided to go mATX. I've been doing some research and came up with this build:
Case: http://www.newegg.com/Product/Product.aspx?Item=N82E16811146065
MOBO: http://www.newegg.com/Product/Product.aspx?Item=N82E16813130657
GPU: http://www.newegg.com/Product/Product.aspx?Item=N82E16814130826
PSU: http://www.newegg.com/Product/Product.aspx?Item=N82E16817171068
CPU: http://www.newegg.com/Product/Product.aspx?Item=N82E16819103727
RAM: http://www.newegg.com/Product/Product.aspx?Item=N82E16820233186
HDD: http://www.newegg.com/Product/Product.aspx?Item=N82E16822236338
Keyboard: http://www.newegg.com/Product/Product.aspx?Item=N82E16823129006
Mouse: http://www.newegg.com/Product/Product.aspx?Item=N82E16826570014
Monitor: http://www.newegg.com/Product/Product.aspx?Item=N82E16824009436
Optical Drive: http://www.newegg.com/Product/Product.aspx?Item=N82E16827106276

The total price for this build is $924.89
Are there any parts I should replace for better parts while still keeping below $1K?
Edit: I already have a copy of windows 7 that was given to me by my school IT guy last year.

I would recommend shopping around a bit more for the power supply. I've seen PSUs equivalent to the one you selected for $40 less recently. That HDD seems overpriced as well.

Would also recommend at least a 1080P monitor. You'll be much happier with it and won't pay too much more.

Take a look through the other "new build" threads in the General Hardware section. You may be able to glean enough ideas and deals to get upgrades in the mobo/CPU/GPU areas and keep things within your budget. $1000 is a fairly standard amount, so basically any new build thread will be helpful for you.

^^^ I concur Or if you're near a Microcenter, you could grab the 3570/extreme4 there for ~$280 and bump up your GPU or PSU a notch.

The ASrock ASRock Z77 Extreme4-M LGA is a good board.
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157294

I think I would still take the Z77 Extreme3 over the 4-M. Better power phase. If you don't need micro-ATX, I would go full size.

He said mATX, but the case in my build is only 2" taller and 1" thicker than the case he listed.

Well I want to go mATX because I do have lan parties at friends homes often and I hate lugging my huge case to their houses. I also don't need to have 2 separate pc's for home and lan parties. I'm not made of money xD Thanks for the tips, they are much appreciated.