If you are on a ~tight budget I suggest covering the entire yurt with poly tarps to solve your concerns. Cover the wall with several tarps that are 6x12 or so and lap the edges secure with tension bands.
Cover the top with a tarp big enough to lap down the wall a couple feet. Double the rafter length, add the smokehole/dome diameter and add 4' to that. Get a squre tarp that size.
Make a slit in the tarp from the edge to a 2' diameter hole you rough cut in the center. Lay the tarp on the roof centering the rough sized hole over the center hole. Then Lap the cut edge of the tarp over eachother until it snugly fits the cone shape of your roof. 'Gorilla Tape' the outside and inside seams. Fine cut the upper hole as necessary once you get the tarp in position. This is how I fit my own tarp to the roof of my 16' yurt. 'On the money' fit.
The poly tarp will also act as an
layer in addition to solving any leakage problems, plus cut down on drafts. Keep the dry wood heat on and the smokehole or
vent cracked as necessary to help expel
.
This is the cheapest solution I can think of to solve your problems. Try it and if it works, great. If other issues come up, well...it's a learning experience and you aren't out a ton of money. If I lived in my yurt year around my choice for insulation would absolutely be felt. But that ain't cheap by any stretch. Good luck.