You need lots of evidence, letters, air ticket stubbs, emails, phone bills, etc, and lots of photo's when you are there. Take it all with you, and fill out the forms. She can then post them after you've left when she is certain in her mind what she wants.
As for your income, if your that well off I'll live with you
Advice - Get a place of your own now. Makes it look better on the application, although it doesn't really matter.
Look here http://www.ukvacs.net/
She may be able to work as a carer, but not for two years legally. To be a nurse, she would have to start studies from day 1, and you will have to pay.
You do not need to go to the embassy, UKVACS do it all.
*This answer is written in an erratic manner as that is the way my brain works
