If you need to stay at the Sheraton CDG specifically, you should be able to find ways to get your account 4800 point threshold for a cash and points night. The Sheraton CDG generally has tons of cash and points inventory.
-Are any of your other Amex cards earning membership rewards points? If so, transfer those MRs to starpoints.
-Buy some flowers--$80 worth of 1-800-FLOWERS should get you 800 starpoints.
Alternatively, if you just need a hotel in the CDG area, I'd suggest priceline. I've stayed at the Sheraton CDG, and haven't found it be anything too special, especially for the price.