What to do with a low-battery 2011 Nissan Leaf?

Our Nissan Leaf is now barely able to make it to town and back, the low battery alarm coming on nearly every time. While I think I'm handy enough to be able to install a new battery, from what I read on this subreddit, a 40kwh battery and adapters will cost far more than the car is worth.

Are there any other options to improve the car besides just trading it in and buying a new car?