I'd switch to this PSU, i think they're both the same price.
If you can find a cheap kit, 1600 Mhz memory will be better, it's sometimes only a few dollars difference. Whether you need 4 or 8 GB is up to you. 4GB should get you by if you aren't running a lot of programs and tabs.
You might also want to check the combos with your APU. Newegg is offering a lot of combos with APU + motherboard. A55 chipset is alright if you're cutting costs, but an A75 has USB3 and SATA3.
What kind of gaming are you doing, even on the low end?