You CAN file jointly with your wife, even if she is NOT in the United States.
You will have to submit Form w-7 with notarized photocpy of her passport picture page, and she may need to get an apostille to certify the authenticity of her passport.
Further, SHE has to sign both the Form W-7 AND the tax return, so it will take a bit of time to get the return submitted and processed.
But it CAN be done; I do it every year for at least ten clients who have spouses in their home countries.
If you need professional help filing your return, email me at
[email protected].