Contrary to popular belief, pouring non Mevushol wine by a Nochri renders it non-kosher. …… Just touching the [already open] bottle, without pouring it, does nothing to render it unfit.
As for attending Goyish parties, having been at some xmas parties at my work place, irrespective of whether allowed to be there or not, simply the Tumoh of such an atmosphere, is enough to make my Neshomo get out of there as fast as possible; i.e Quickly eat the Kosher meal they supply me, and depart right away.