Germany Tax

I think one always has the theoretical option to make a joint tax return with their spouse if they are living together - or an individual one. The problem with the join return used to be that the spouse had to sign it, something not really possible if she is in India. But now all returns are to be submitted electronically over a program called Elster, which means one cannot really sign. But for such details you should simply ask the Finanazamt. They don't help you to fill out forms, for that you need a tax advisor or Steuerberater. But about basic requirements they have to answer your questions. Just go to their offices, take a number and you'll get to talk to someone who should be able to help.

Tom is right: For procedural and formal issued, ask the Finanzamt (tax authority).
But for other ta-related matters, you need to engage a tax consultant. They have a monopoly on giving tax advice (and fixed fees).
To my understanding, any marriage-related advantage only applies if the spouse also lives in Germany (or possibly EU), in the best case together with you. The same applies to child-related reliefs or rebates (e.g. Kindergeld).
The tax class, however, has no influence on your final tax bill (which is calculated from your yearly tax declaration) - it only determines the height of monthly deductions from your salary as pre-payment on your final bill.
I would expect your tax bill, without family members around, to be around what you would have been deducted in tax class 1, but the exact specifics (and how to declare everything correctly) is something only a tax consultant can tell.