The motherboard may technically work, but I'd avoid it for a couple of reasons. Firstly AsRock boards aren't that good, you would be better getting one from Gigabyte/ASUS/Biostar, Secondly, your board has the H61 chipset that was designed for Sandy Bridge, this chipset will support Ivy Bridge CPUs but may need a BIOS update to do this, in that case you would need a Sandy Bridge CPU to do the update. You would be best to get a board from Gigabyte/ASUS/Biostar with either a H77 or B75 chipset. This board would be a great option (I have used it in several builds myself) -
http://www.newegg.com/Product/Product.aspx?Item=N82E16813138379I also wouldn't trust that PSU, the PSU is an important part of your computer and should not be cheaped out on. Get something from a reputable brand such as Corsair, Seasonic, or XFX. 300w should be enough for your machine now but you'd also want to consider any future upgrades as adding things like a video card will require substantially more power.
That is also a triple channel kit of RAM - The board has 2 RAM slots so you would need to get a set of, at most, 2 sticks. Best option would be to either get 2x4gb or 2x2gb.