As I said I've spent a lot of time in the Andes, first time went for four months I took an old Ultimate Parka, hollfill insulation and reasonably light for the time (about 1kg). Worn over a base layer shirt (Northcape) and an old style Heli Hanson Blue fiber pile it wasn't warm enough at 5000m.
Second time I went for nearly nine months, this time I took a Rab down jacket same weight as the Ultimate parka but twice as warm. I also took a much warmer sleeping bag and was a lot more comfortable. I still have the down jacket it doesn't get used much in this country but when I go skiing especially in Scandinavia it always goes with me.
Camping out in -10C weather requires the right frame of mind, you seem to be taking it very lightly. "Can I get away without this" "do I really need that". Start taking it seriously or prepare to suffer. Get the best gear you can afford, you can always sell it on afterwards.