I used TwistahXD his solution but would like to add things to speed it up :)
When you get to the point where you have to protect your father (and get tons of valor points like he sed).afther you killed everyone and got your valor points.
Just restart cheqpoint the game tells you : you will lose everything that's not saved BUT you keep you valor points.
So i just protect my father 4times and was able to get over 600k valor points in like 10 minutes.
so instead of runing trough one or 2 missions to get your last points you can do this :) NOTE : when you bought all your upgrades and stuff you have to kill a few enemies for the cheevo to pop up...(at least for me it did )
Grtz Magnificent X
(sorry for bad englisch )