Unless you can confirm an upgrade on the flights you want at the time of booking, with miles (and co-pay as appropriate), your only real option is to purchase a business class ticket.

I think you can usually find US-India in business class for about $4,500-5,000, although it may not be on the carriers/alliance you want (e.g., Air India is likely to be the lowest cost). Austrian through Vienna (via JFK, not sure if they fly to ORD) usually has reasonable fares as well and will earn you BA miles. Alternatively, BA usually isn't too bad.

You don't state your Premier status level, which would be a critical factor in the likelihood of you clearing the mileage upgrade waitlist. Unless you're Platinum or higher, or are flying on a Tuesday or Wednesday, your chances could be well under 50%. As you might imagine, there is a lot of demand for the business class seats on UA's flights to India. I've seen the cabin go out full with only a very small handful of upgrades cleared.

The only upgrade for cash option in advance will be the option to pay the fare difference up to business class. Sometimes they offer discounted cash upgrades at check-in, but I would absolutely not rely on this, it's probably very unlikely for this route.