word choice - What should be the proper reply for thanks?

I like a girl which is in same division as I am. Recently she was suffering from malaria and when I came to know this I sent a "Get well soon!" message. We have hardly exchanged any words in labs and common lectures.
Now she has replied as "thanks!" as expected. I want to give her a good reply for her thanks just to continue. So what should I say in this situation. I really like this girl!