I have shopped online tring to both pinch pennys and get lighter until I am completely information overloaded by manufacturers specs and could use some real world advise. the situation is this, a freind and myself are planning a trip from Springer to Neel's Gap for March or April 2015, this presents me with a couple of problems: (1) I am a cold sleeper, my current bag is a Big Agnes 0* storm king, the last time I used it in cold weather, mid 20's (I am guessing because a 6 oz cup about 3/4 full froze solid) I spent the whole night cold, finally gave up about 4 am and tended the fire until my grandsons got up. We were truck camping so we had a 2 inch memory foam mattress on top of 1 inch of neoprene (armaflex pad), I was wearing a mid weight top and bottom with a fleece 1/4 zip as well.
(2) I can't replace all my gear at once and have winter camps with the scouts coming.

I have decided to replace my thermorest backpackers pad with the xtherm but when it comes to the other of the big three which would be the first to replace, the pack or bag?
I probably should have mentioned I am using a 5.3 pound external frame pack from campmor, I think it is a outdoor research or outdoor products, and also I have settled on a tarp tent from Tarp Tents.

What would you guys and gals who have hiked the area in that time of year suggest for gear and what kind of weather should we expect temp wise??

Thanks in advance for your help and patience.

creek