Hello , I wanted an opinion of you , I wonder what is the best configuration to run new vegas with mods, currently I have a dual core PC ( AMD) + 4GB ( DDR2 ) + GTS650ti 2GB and I can not play the way I want , what is the best setting?

You could checkout the Large Address Aware 4GB patch on nexus, my game was lagging when i started downloading mods, i thought i need a more RAM untill i found out about this  Large Address Aware executable mod, it helps my game run a lot faster,

not sure if you already have this already:
https://www.youtube.com/watch?v=nzJze2d4QKU

Im using a quad core pc + Intel(R) core(TM) i7-3820 CPU @ 3.60GHz processor +  GTX470 video card:
im also running the game with high quality texture packs + high settings blackout ENB, and my game runs very smooth with the help from the 4GB(NVSE) enabler.