The EAD is automatically extended for aditional 6 months if u had applied for one initially , if you apply for EAD now you will be provided with a new EAD until the Expiration of TPS in 2018. I think you can because you are suppose to get one now or later you can just fill I-765 and put TPS category c (**) Whatever it is attached with a TPS approval notice which has TPS valid thru date. USCIS will have to issue you EAD until the expiration of TPS.

**This is my personal guess, I'm not a immigration attorney.