I'm not sure you have to do anything just yet. The health of your RBs is the biggest thing to me. With Brown, it seems like a matter of time before he gets hurt. Same with Williams. Williams was actually pretty good last year, but health is always a concern. You might want to grab Huggins, but not sure who you would drop to do that, so it's tough there.
Are there any teams who are really weak at WR? Target them. Heck, all of you WRs could put up points this year, so someone in your league has to be looking at their WRs and wondering how they will do.
12 Team League. We start 2 QBs and get .5 PPR, otherwise standard scoring
QBs: Stafford, Fitzpatrick, Collins
RBs: Charles, Mendenhall, Best, Starks, Carter, Karim
WRs: D. Jackson, Marshall, S. Smith, Green,
TE: Hernandez, Cook