My first PC build

Hi there! I am planning this Christmas to build my first pc here are the specs

Amd Athlon X4 750x

xfx radeon hd 7770 ghz edition

4gb of 1600mhz ram

msi fm2-a75ma-e35 matx

If there are any upgrades that I could make without out crossing the £450 mark

all of these parts were selected on PCpartpicker...if that matters. It costs currently £402

including case, power supply etc  

Replace the 7770 with this one : 

XFX Radeon HD 7850 2GB + 2 Games for $119.99

Or you can get the 

Diamond Radeon HD 7870 Ghz Edition 2 GB + 2 Games for $170

That would exceed your max budget by $20, but what's $20 now a days?