I read it in a letter where the girl was signing it off. The rough idea I get but I want to know what does the extra 'noch' do to the overall meaning of this fragment.
In spoken language, it is used, when a talk is cut short: There wasn't time to talk extensively about the person concerned. But the person should at least be greeted, so the greetings are "added" to the end of the talk.
I haven't seen it used in a letter and wouldn't do so, because it looks as a PS with important content. One get's the impression that the writer didn't think about the letter in before hand or had to short cut the letter due to time limitations.