First of all.. why in earth is JSTEW still on your roster? Get Goodson if you can!
I agree that you for sure need to upgrade at RB. You won't be able to win in the playoffs with what you have. Dre is, well, Dre, but I think you should sell him if you can and get a beter WR than Manningham? Obvoiusly CJ is a stud with great playoff matchups.
The bottom line is: if you can get a better trade that what is out there, take it. I.e.e maybe a lesean McCoy, Frank Gore level player along with a better WR? People think CJ is this god but the difference between him and some of the other guys I mentioned isn't as large as people think. If you can make any deals to get better recievers with those, then take it.
If not... Take the offer on the table. Hopefully this helps and wasn't too confusing.