Extracting gbxml file from Revit to OpenStudio for building energy modeling

Hi, I'm looking for a freelancer to help me extract a gbxml file from a Revit model file and then import it in OpenStudio for energy modeling of a building. I have the Revit model file ready for use and just need someone to extract the basic building geometry needed for the gbxml file. I'm looking for this project to be completed urgently within a week if possible.