Upgrading first AMD Desktop - Need help choosing the right parts

So I am looking to upgrade my AMD PC, however i know nothing much about AMD, other then its mostly used for gaming and video editing PC builds.

This is the specs of the PC right now;

Microsoft Windows 7 Home Premium 64-bit SP1
CPU -AMD A4-3300 Llano 32nm Technology
RAM 4.00 GB DDR3 @ 665MHz
Motherboard Foxconn A55MX (P0)
Graphics W2261 (1280x960@60Hz) AMD Radeon HD 6410D
Hard Drives 298GB Western Digital WDC WD3200BPVT-00JJ5T0 ATA Device (SATA)
PSU Antec basiq 500w

And this is what i would like to put into it;
CPU - AMD Athlon II X4 651K Black Edition 3GHz
RAM - Crucial 8GB DDR3 1333MHz Memory
Graphics card - PowerColor HD 6570 1GB DDR3
PSU - Antec VP 550W

I'll mainly be using the pc for web browsing/Skype/Spotify or Itunes (all at the same time), gamng (never going over low or medium settings, i prefer performance over graphics) and streaming (xspilt/OBS)

Iv already noticed that the RAM is painfully slow, and needs to be upgraded asap.

1st question: is this enough to support what i need out of the pc? I have a feeling i might need a better Graphics card.

2nd question: If i was to only install the RAM which i plan to buy, would it help boost the pc's performance while i save up for the other parts?, or may i just wait till i install all the parts that need upgrading along with it?

Thanks in advance