The 4570 has a locked multiplier; you can't overclock to any worthwhile degree.
Eliminate the cost of water cooling, and you can make that a 4670K and a Z87 based motherboard. Add a $20 cooler like the cm hyper212 and you can get a modest overclock.
And... a single 1x4gb ram stick will operate in single channel mode. 2 x 2gb is better.
Verify it's an i5-4570 and not an i5-4570K (the "K" means unlockable/overclockable).
If you're using the STOCK cooler though I would suggest something quieter like a Cooler Master Hyper 212 EVO. I also agree with the DDR3 memory comment.
*Buy an IDENTICAL 4GB stick and setup like THIS:
1) See motherboard manual (probably 2nd and 4th slots)
2) Click "XMP" in the BIOS to auto-apply the RAM settings (verify it is 1600MHz)
3) Save settings
4) Reboot and run Memtest via DVD/CD or USB (can use IMGBURN for the DVD; may need to change Boot Order in the BIOS to the DVD/USB device so it boots before the hard drive).
If the op already owns the rig and specs, then water cooling will be a complete waste.
It will add expense and noise and do no good.
Overclocking by raising the base clock by 2% might be possible, but is not worth it.
Adding ram will not improve cpu processing speeds significantly either. But the added ram always helps to cache more code.
If you have the $100 or so for water cooling, I suggest you use it for a ssd for the os and some apps. It is a much better performance enhancer.
If you already own the parts, enjoy, it is a decent rig.
If this is a prospective build, the first thing I would do is change to a 2 stick ram configuration.
Ram is cheap, and a 2 x 2gb or 2 x 4gb would run in faster dual channel mode.
Since you have extra budget for water cooling, I might make the following suggestions:
1. The caviar blue is not the fastest of hard drives.
Consider instead using a SSD. I will no longer build anything without one. It makes everything you do feel so much snappier.A 120gb ssd will hold the os and a handful of games. Better yet, a 240gb ssd will hold a good number of games. If you should ever need more storage, it is easy to add a hard drive later.
2. For gaming, the graphics card is all important; more so than the cpu.
A balanced gamer will spend 2x the cpu cost on the graphics card.
Consider a GTX770.