If you don't want to spend 1 - 1,5 hours (or whatever you use) to clear the first wing in Icecrown to get a few upgrades that might make the new fights a tiny bit easier to deal with then extend the save.
Or if server rank is very important to you try to start the raid earlier? A bit short notice perhaps, but maybe in two weeks when the next wing comes this is something you can try out.
Personally I'd say that if you just killed Saurfang this late that you should focus on the semi-farmed content first because of two factors. 1) You need it so your players will be more comfortable there and will be able to clear it even quicker next reset so that you will spend less time with known content. 2) Server rank isn't really all that important and epeen-ish when it's a kill in normal mode. If you can dip into the top 5 or top 10 server wide at the end boss in normal that will most likely look better than a server second on a boss noone really cares that much about, unless it's the end of the wing boss then maybe it would look a tiny bit better.
"We have two ears and one mouth for a reason." - Buddhist belief.