What form does my co-sponsor need?

Assuming that the I-130 for your visa was sent to USCIS, when NVC sends out the I-864 to your spouse/petitioner/sponsor, your spouse will provide an I-864 and financial evidence such as IRS returns, employer letter, and pay stubs, the Joint Sponsor will provide to your spouse another I-864 and financials, to send in together to NVC.

If DCF then your spouse will send both I-864 packages to you for the visa interview.

http://www.visajourney.com/timeline/profile.php?id=46071 (Having no timeline leaves us all in the dark as to where you are on your immigrations process)

Thank you very much