Hope you dont mind if I add my point of view here.
Looking at your gear, I would say you have pretty competetive runed set, which should be enough to combat most ppl at L3-4. Ofcourse, if you want absolute domination, then the best possible rune is always available. Conventionally the blue runes at 3-4 were always enough, but if your pocket is deep, why not grab these beauties?:
For your class at L3-4
Vest
Shirt
Wep (main)
Aux
Pauldron
Keep in mind these are very expensive, hence acquiring them would result a pretty deep hole in your pocket. Furthermore you wont be in L4 forever, hence the option of opting out from getting the rune for vest can be justifiable. Other than that these purple runes does make a pretty big impact over the blue and ofcourse the green ones you wear.
Although if I was you Id just keep what you have for now and concentrate to purple rune L6+ gears for absolute domination in Talaars and onwards.