Japanese for: Get Well / Thinking of you

I want to write a card for a Japanese friend who was in a bad car accident. She is intensive care at the hospital and the situation is very serious. What should I write in the card? I know お大事に means 'get well soon' but this sounds a little trivial for someone who is in a severe condition. Please tell me what to write.

I don't know how fluent you are with the language, but if you are to some extent, something like:
お大事になさってください。(Please do take good care of yourself.)
一日も早いご快復を心よりお祈り申し上げます。(My sincere hopes that you will recover soon.)

(All in polite, formal speech.)

Frankly, I feel that "odaijini" is as trivial as 'Get Well' / 'Thinking of you'. If you feel that you need to express your thoughts, then express your real thoughts rather than the usual greetings.