Hi, hopefully I can get an answer to this in the next hour or so!! 
I
am taking DS to a shower today and I usually bottle feed when we are
out because it is just easier. I have been keeping formula on hand that
we use sometimes when I can't pump, but I have none. I have frozen BM,
how does it work, can I bring it with me frozen and try to thaw it
later? FWIW its really cold here so the car ride shouldn't be an
issue... I just don't have time to thaw it at home. How long will it
last at room temp once I take it out? Any suggestions appreciated..
gotta go try to pump some more now!!

TIA!
Re: XP: Thawed Breastmilk??
I defrost my frozen milk in the fridge and it takes overnight plus some time on the counter. If you defrost it, it needs to be used within 24 hours of being completely melted. If you're definately going to need it, I would say to defrost it in a bowl of cool water, that'll do it pretty quick. If you heat it (aka defrost and let sit in hot/warm water) it should be used in an hour.
Have fun!