OK New Guy, here's a few tips:
For women's sizes. it sounds like you are probably an 18 or 20. There's a size chart on this website that may help:
http://www.jessicalondon.com/Help/Help_SizeCharts.aspx
You really need to try things on in a store to know for sure what will fit.
Assuming you don't want to spend a lot of money on a one time event, I suggest you find a thrift shop (Goodwill, Salvation Army, etc.) and see what you can find in the way of clothing.
For makeup, I suggest that on the day of your party, you make arrangements to go to a MAC, Ulta, or even the cosmetics department of a major department store and have one of their professionals do your makeup. You can do that with or without wearing your femme outfit.
You can cover leg hair with opaque pantyhose. Depending on how dense and dark the hair is, you might need to wear two pair. A pair of fishnet hose over some opaque hose will add to the "****ty" look.
If you can't shave your chest, you had better select a dress or top that covers it. You could use a rubber "treasure chest", but those things look fake and are not very comfortable.
And to fill out a bra, if you don't want to drop a bundle, you can stuff it with socks, water balloons, or nylons filled with birdseed.
Good luck, and have fun with your day as a woman!