Agreed ... might want to trade a WR for a top tier running back.
I'd be worried about your RBs. You're counting on him to start all 16 games this year (or at least the first 15), something that he has failed to do 3 out of the 4 seasons he been in the league. After that, all you have is a rookie who may be splitting time with Ricky Williams.
Meanwhile, you have 4 WRs that are ranked in the top 15-20 at their position for fantasy football. Two are in the top 5. That's a lot of strength at one position, and very little at RB. Considering that RB is considered the key position in fantasy football, I'd try to do something to remedy that.
You already have a bunch of High risk/high reward type players at RB, so I'd go looking for an every-week stud player. You should be able to trade away one of your top receivers, get a top five back, and still have a strong set of WRs.
If you don't want to do that, you can see if Mwelde is on the waiver wire, and pick him up in case Bennett goes down. You can always drop one of your kickers to make room for him. There should be a kick available in week 3 or 4 to fill in for your starter.