Wedding is late October in upstate NY. I know I"ve got time, but I like to keep my eyes out for good sales. The invite doesn't say anything about attire.

I will be nursing a 6 month old, who is coming with us to the wedding. We will be staying about 2 hours away, so I need to be able to sit in it without becoming a total wrinkly mess (or I guess I could try to change in the car when we get there).

I was thinking about getting a simple black wrap dress. I have a couple beautiful wool skirts that I"d like to wear- but I"m not sure they will fit at that time.
Can I wear a wrap dress like this: http://bananarepublic.gap.com/browse/product.do?cid=69885&vid=1&pid=560209002
with tights, boots, and a sweater? If I can get into the skirts, what kind of top would I wear to make it wedding appropriate. Would a simple cashmere v-neck work? Can I wear flat ankle boots (they are black suede- and in way better condition than my mid-calf brown boots)?
I don't really do heels, ever. If you tell me I need another pair of tall boots, I will totally believe you and start shopping now

My husband and I are chronically over or under dressed for every wedding we go to. Hellllp.