Well your ram speed is very slow ddr3 memory. For $75 you should be able to get some 16Gb of 1333 or 1600mhz ram.
Another upgrade would be to get a second SSD for cache and scratch disk data for video rendering.
Lime the other poster said a GPU upgrade would also be a great idea if your editing program uses gpu power too. What's the video editing programs being used?
you do know that his ram is dual channel meaning 667 x2? euqals 1333mhz....