Good luck (and congratulations on the contract)!
Here is a link to a blog I wrote the year the energy aduits became a requirement. There are several energy auditors listed. I suggest you call a few and see who offers the best rates. I wish you luck on your condo sale.
Betina Foreman- Realtor, C.N.E.
Austin Home Girls Realty
Good luck and please let me know if you have any questions.