I feel all the better for seeing you.

You can also say, "Hey it's great to see you too!"

Inasmuch as "how are you?" is usually a rhetorical question, a non-standard response might not be received well, depending on the person. Of course, the usual response is "fine". To respond in a non-standard way as this, one would need to know the person well.

Yes there is. :) Actually, we have the exact same phrase in English. It means that although the person was not having a good time, they are happy to see the other person arrive. It is a clever way to say this, because it carries all this meaning in a simple way.