I would recommend getting her into a warm dry place - like inside a warm mudroom or part of the house. In a box with some warm bedding either a towel or some shavings. I wouldn't hesitate if she is chilled now it doesn't take long.
Should have been more clear -
A) If she is acting chilled - you might want to offer her room temperature yogurt or a scrambled egg w/ a bit of warmed cat food if you have it available. For a boost maybe a bit of lightly warmed water with a little, little bit of sugar.
B) The symptoms sounds like sour crop, if she has more vomiting or sour smelling burps, massaging (primarily downward) will help to move the gas/obstruction. If this is the case hold off on the food and offer her lightly warm water with a drop or two of Apple Cider Vinegar. Once the crop has reduced then a bit of a treat is nice.
Please update and let us know how the girl is faring.
Anyone else?