do not pair the G4560 up with ddr3 ram, some boards support it but with the voltages you will surely damage the cpu over time. If you are sure to go with the G4560 then you must get ddr4 ram to ensure that the chip will not be damaged by higher voltages.
Like wildcard said a good budget gaming graphics card would be the GTX 750 or 750ti, these go for around £50 (UK) second hand on ebay and work very well for playing most up to date games.