Here is what I do when I know I have a party to go to. I am also on WW, have lost 23 pounds and have attended many a party since September.
First of all, bulk up in the early part of the day. An egg white omelet with a slice of 2% cheese, lots of veggies in it is still only 1 to 2 points. My DH chops up 2 Morningstar Farms vegetarian sausage in there for another point and I can last until 2 in the afternoon without being hungry for only 3 points. Sometimes I add a lite English muffin for a 4th point, but I have had a feast if I eat this.
Before I get dressed to go, I try to eat a big salad with low fat dressing (1 point)or a can of green beans or beets or another free veggie. That way, I am not starved when I get there.
Drink water or decaf tea throughout the day.
Save points throughout the week if you know you have plans later in the week.
Try to focus on the event, not the food when you get there. Figure out as soon as possible where you are going to spend your points. I am a real sweets person, and always make sure to have at least some of the cake/cookies/etc.
I find that I rarely go over my points if I do this, and sometimes eating like this helps my metabolism and I even lose more that week!
Good luck and enjoy the shower.