Wanna buy a monitor for this build!

Well the 660 should do a decent job on most games at 1080p, but 720p is always going to be faster because its' a lot less pixels. 1080p monitor opens up 1080p movies, youtube, etc as well and more screen real estate, so it's a toss up. Does she want her games to look awesome and not care if it's a lower resolution or may have to turn down a few things to do it at 1080p

yes she's willing to max out games even crysis 3. i found a good 1600x900 monitor for $90 can it do a good job on that? also do you think the b75 mobo can boost the i5 3470 up to 3.6 ghz?

Get a 1080p monitor if you can, you can always lower the resolution of the game if 1080p is too much for that card (which in most games it shouldn't be).
This is a cheap 1080p monitor, though it still may be out of your budget.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Just remember that the monitor will last longer than the rig. My BenqG2420HD was bought ~5yrs ago and has lasted me through three different builds. Getting a good one is important, because you'l have it for a while.

Nope, cant overclock on B75 (I think) and the processor is locked, so you cant overclock the chip even if you had a Z77 mobo. Turbo Boost should still be active though.

Go to salvation army and pick up a 1280 x 1024 monitor for $30, that is what I did. In fact sometimes they have half off days where the monitor is $15, I got a second one then.

so will that b75 mobo turbo boost the i5 3470 up to 3.8?
also what do you think about my psu? should i have bought a better one? actually i can return it for a better one... any suggestions? (bare in mind that she'll oc the gpu)

p.s take a look at this psu and tell me what you think
http://www.coolermaster.com/product.php?product_id=3686