Amy had gone on adventures with River before, of course, but she hadn't yet had the opportunity to speak with her since River had arrived in Lawrence, Kansas. The entire situation was a little odd - arriving in a different part of the country, without a ride in the TARDIS? Well, Amy hadn't had that happen before. But it wasn't terrible here, even if it was a bit odd. And with the Doctor, if not her Doctor exactly, and Rory, and River all here it was almost precisely like one of her adventures.
She stepped in and seeing River she waved at her and quickly walked across. "River, how have you been? It's good to see you again."