I'm not sure I can visualize the set-up, but would it help for you to sit in the chair rather than on the couch? Does that get you closer? If not, it's pretty common that social space is about 4' apart. That would correspond to @ the distance my T's chairs were. If you're further apart than that no wonder you feel out in the cold.

You could state your feeling of being uncomfortably far away, and ask if there's any reason you can't move closer. So you're asking if you can move, rather than asking her to move. That you can reference how it's different from the old office also makes it a bit less awkward.