Covered Porch Support Concrete Crack
Is that post directly above, leaning? If so, foundation is settling and that is a bigger problem. If not, then the crack has probably developed from water seeping into the concrete around the anchor that is holding the post, then the water freezes and cracks the wall. Fixing the concrete without sealing the crack around the post anchor, will allow water to seep back into wall, freeze and then crack the wall again. 

"No" you can't slow it down and "no" you can't do it yourself. If the foundation is not settling, the best way is to remove the concrete that has cracked away from the main foundation and re-pour a new section of concrete to match existing. (You can't re-pin the broken portion back to the main foundation.)