I say, stand pat with Trubisky and Foles, and look for a developmental-type QB in the 4th to 6th rounds. Both Trubisky and Foles have had good games this season, and I think the issue is more RB and to an extent, O-Line, not QB. If the Bears had signed Adrian Peterson, I think they're in much better shape.
Cohen and Patterson are not full-time RBs. You can line them up, they are dynamic return threats, they can explode when they get the ball, but they're not guys you can hand the ball off to 10-15 times a game, much less 20.
What the team will need is a way to get more picks. The first option, trade down. Multiple times, if need be. At First-Pick.com, I often can trade down from a mid-first to get 2-3 more second-round draft picks. A top 10 pick can be leveraged to get as many as 4 more. If someone blows me away with a wealth of picks for Robinson, I'll go with that, but ideally, I sign Robinson to an extension.