I would like to purchase a replacement tank only. Our pump is good, however, the tank has a small hole.

Yep. For instance, Shop well pressure tank at Lowes.com: Search Results!

You will need to know the approximate size of your current tank and whether it is a bladder tank (most of them are).

We have to know what tank you wish to purchase. If it is a toilet tank purchase a water saver from the same manufacturer . If it is a bladder tank then you may either bush or adapt to the hole back to the system. Good luck, Tom