15 year old liner is failing

I need help! My liner is 15+ years old. It started falling away from the walls. I tried to do a temporary fix to survive this year and save money for a new liner but its not working. :-( My pool is a 21x36 in ground . My question is what do I need to do to preserve my pool so it isn't completely ruined? I know I am going to have to put the cover back on and start over next spring. So do I need to drain? Cover exposed wall with tarp? Any help would be greatly appreciated.
Thankd

Fix it ASAP. Liner pools do not do well without liners or water. If you can borrow money and fix it this fall (a little cheaper than mid-summer), do so. The cost is likely to go up as the pool sits and deteriorates.

I'll see if Ted (Waste) has further thoughts to add.